So I was thinking about you and about Sheik and I'm going to just roll with what my thoughts were while I was washing dishes today. I'll try to give a general overlay of the matchup (take this with a grain of salt, as I'm not anywhere near being 'notably OK' at this game, but I promised to do this and never did
) And then I'll give you some thoughts on your matches. Again, sorry for not doing this sooner even when I had said I would. :\
So, the matchup from our side takes a good deal of patience (as do all of our MUs, but this one specifically), because Sheik is REALLY good at spanking us when we try to approach her. Retreating fair is probably your best friend in the neutral game, versus her standard aggression (which revolves around spacing SH fairs, which beats our CC/shield when done well). You can usually set these up a number of ways, including floating around FJ height (perhaps a bit lower) and trying to bait her to swing at you, then moving back and smacking her, or reacting to her SH fairs and jumping backwards into a float. Usually, the issue with jumping vs Sheik is that she'll hit us when we try, but backjump solves this, because you're moving away from her while setting up your float.
The other part of the neutral game, the ground game, is a bit trickier (due to needles + SH fair), but Peach manages with smart shielding of needles, and a good deal of WD back to keep her mobile against Sheik's approaches. Try not to hold shield too long, because Sheik's SH fair > jab/SH fair pressure is dangerous, and the windows where she's open are kind of difficult to find. And avoid trying to just CC > downsmash it (unless the Sheik spaces poorly), because it generally doesn't work. You've got to stay mobile in this MU, and neither downsmash nor prolonged shielding help you in those instances.
I find turnips OK here, because Sheik has to deal with them, and you can use these decisions she makes against her. Firstly, remember that pulling turnips vs her is riskier/harder to do than it is in most MUs, because most Sheiks will needle a Peach on the ground, especially if they expect you to pull a turnip. Be very careful about how you pull them (if she's on a platform that is not level with you, you can pull them, or if she's doing some unnecessary movements [watch her closely for these]). But yeah, turnips are a projectile she has to deal with cause they do 7% - 34% randomly and they limit her movement. You've got license to be more aggressive vs her if she's shielding them, because a shielding Sheik is very good for Peach provided your tech skill is very good. Make sure it's very good (I'll expand on hitting her shield a bit later). If she's trying to jump over them to get to platforms, or to counterattack your throw lag, take note of this and adapt accordingly (a jumping Sheik can be hit by SH/FJ fairs/uairs once you learn how she's doing them, and a landing Sheik can be dash attacked, which leads to big combos).
Again, don't approach Sheik straight from neutral unless you're 100% not worried about the player at all. This means don't float fair towards her, don't dash attack towards her UNLESS she's landing from an aerial (like bair), or in general, and is at or above 40%. And other similar things. This is far from everything you need to know about Sheik at neutral, but hopefully it's a decent start.
So, you've taken center stage from Sheik, or you've got her in her shield somehow. Now what? Well, you LOVE center stage. Peach is amazing with it, and Sheik is kind of worse without it (but you need to respect her, still). With center stage, you've got more space to retreat to stuff her attempts to stage the center from you, and she doesn't have the space to do the same (still respect her, though). Look for how she's trying to escape. Most people don't try to attack Peach directly when she has center stage. Instead, they try to go over you, or fake going over you to get you to swing and lose that stage you have. Look for this. Don't try to fair into her just because she has no stage (her ftilt is very good vs our float, and if she calls it, suddenly you're in a combo and your control is gone). Don't try to dash attack. If she's trying to jump over you, uair is very good for punishing her from around 35-65% (you'll need to test these percents yourself, as I don't remember the exact range where uair combos into another aerial), because she's got bad mobility in the air, and you can combo her. Uair is good in general if she's trying to jump over you, because again, Sheik's aerial mobility is pretty bad, and you can abuse this. Alternatively, you can smack her with fair/nair to push her back to the edge/offstage. Maintain your stage control without over-committing.
So you have Sheik in shield? Good. This is where you need to have your tech skill as good as it can be. Sheik's grab hurts. A lot. So try not to get shield grabbed during pressure. Her shield is really big, so unless you've worn it down some already (I find float > dair to be pretty good at safely eating her shield), I advise against downsmashing it. Savvy Sheiks will WD OOS > grab you for it and it'll hurt. Or you just won't accomplish anything except for whittling her shield (which is good if she decides to use it again soon, but not something you should aim for). I find FC fair (make sure this is a low fair) > grab a VERY powerful option. In general, grabbing Sheik is very, very good. It allows you to push her out of the center and towards the edge where she doesn't have control, you can sometimes combo her off of it (uthrow > uair/nair works in the 30s, but unfortunately you'll have to test this too, as I usually play it by ear and so I don't have the exact range memorized), and it makes her more reluctant to shield. So you're conditioning her to not shield so she can get hit more. It's pretty good. Despite what I mentioned about uthrow, you generally want to throw Sheik towards the ledge, and DON'T commit to something. Just try to see if you can react to what she does after that (set yourself up properly to react, with an appropriate float height, or a DD/WD...anything where you can position yourself to punish what she doesn't while remaining safe). Try not to fthrow her when she's at super low percents. If she's in the center, bthrow does a decent amount of damage, and downthrow is alright for a "techchase" situation (which will often end up in you trying to abuse the position she's in, and not a direct punish).
There is a range just outside of her shield grab where if you FC fair her shield and expect her to shield grab, you can go for a dtilt afterwards, and if you did it properly, the dtilt will punish the whiffed grab and give you a free combo. FC fair > jab is decent if, again, you're expecting her to shield grab. It interrupts the grab and then you can downsmash/grab her. I *think* it interrupts attempts at rolls, too, but don't quote me on that.
There isn't too much to know about handling getting grabbed by Sheik, tbh. There isn't THAT much you can do at kill percents if she knows how to combo from grab. DI in on her throw at super low percents, and DI away at all other percents. DI away on her ftilts, fairs, jabs, uairs, nairs (you might want to SDI her fairs/ftilts/jabs).
As for edgeguarding Sheik...this part is kind of trickier than it seems because she actually has a lot of options while she retains her doublejump. It depends on where you are on the stage. Firstly, you need to know that if she can DJ back onto the stage/ledge before you can get there, you will most likely have to just watch her shino stall on the ledge for however long she feels like. :\ Pull a turnip and keep your center stage. Remember that her position is worse than yours.
If you can, reverse turnip throw to get to the ledge > float is good, because you can move to the ledge while your back is to it, so you don't have to turn around once you get there. The float puts you in a good position to hit her DJ with an aerial (or just bait a swing from her and hitting that). When she's around ledge height, you can sometimes toss a turnip to hit her out of her DJ and knock her further away. When her DJ expires, make sure you grab the ledge if you can. Watch out for the poof, though (right before Sheik poofs, she's doing a sort of flip in the air. It's in the beginning of her upB and there are a few frames before the poof where she's vulnerable. I've seen Armada dair Sheiks out of their upBs; this might be worth going for).
You're under 100% and you grabbed the ledge. If Sheik upBs and lands close enough to the edge (you should be able to relatively judge how close she'll be to the ledge from where she is when she upBs, but Sheiks can be tricky about this), you can ledgestand > downsmash (Sheik can hold down for the first hit to get hit back onstage, so watch for this). Ledgestand > reverse nair solves this (especially at 90+ percents), but be careful for Sheik ground teching this (I haven't seen many do this, however). You can also dtilt > reverse nair her if the percent is right (60-ish? I wish I had actual percents for you. I apologize). But yeah, in general, watch for her double jump first. Don't try to get the ledge if she's close to it while she retains her DJ, it's futile. Just pull a turnip and wait for what she does from the ledge (she'll shino stall to make you unsure of when she's coming up, so beware of that, as well as her ledgedash).
As far as stages go, it comes down to preference for the most part. Yoshi's is risky, but OK for Peach as long as you can apply pressure, I think FD is strong for her, too. DL/FoD are decent stages, but Sheik is strong at those places as well. I would personally stay away from BF/Stadium. Hopefully all of this makes sense. If any of it is confusing/poorly stated/outright incorrect, let me know so we can go over it.
Ok. Onto your video.
At the beginning, you start off patient when you see that the Sheik is representing a more reserved type of game. He goes straight to the top platform, and you don't overcommit trying to hit him. Good.
25:37 I think, after that nair, when you saw him shielding, you should've floated, and initiated some pressure on his shield.
25:39 Weird exchange. It was a good jab by him, but I *think* you could've CC > downsmashed it, rather than jumping while he was facing you. Alternatively, instead of FC nair > jabbing his shield, you could've grabbed it. I think that would've been better. But I don't think what you did was "bad," really. He just reacted well.
25:40 After the downsmash, you immediately try to go into him to hit him. Instead of that, you could've done WD back > float, or back jump > float. Alternatively, I suppose FJ nair would've caught him out of his own FJ, and would've been better, there. This interaction tells me that you need to focus more on watching your opponent. And then you get comboed out of impatience. I know you want to get back on, but it is almost always better to wait (and not DI inward).
Note: When you ledgejump, hold away so it's harder for your opponent to hit you out of it.
25:48 After getting back, you try to nair into him again. And then you shield. It's hard dealing with Sheik when you have no stage, but there's no need to make it worse by doing that.
25:53 The Sheik gives you some stage, and you run in to dash attack. You could've most certainly reacted to (or at least anticipated) his FJ, and wavedashed back after your dash forward. Then you could've gone into a float and worked from there.
25:55 The roll in was bad.
26:00 A dash attack punish would've been very good for you here, but he shielded. Not sure exactly what you could've done here, since you messed up the nair. I guess this is a note that your tech skill (yes, even as a Peach) is extremely important. You've got to be smooth and mobile.
26:07 Not sure what you wanted after the fair, but grab > pretty much anything else. You could've thrown him behind you, and worked with that.
26:15 You could've pulled a turnip here. Look at where you are, and where he is.
26:18 He is a LOT closer now, and that was not a good turnip pull.
26:23 After you knocked him off, you could've grabbed the ledge here. Something I've been experimenting with (it's not really new at all, but I don't see that many Peaches use it) is ledgefloating. You just turn around and jump onto the ledge (without using your float). Then you hold away and very quickly input float.You're now floating from the ledge and in a position to threaten to aerial the Sheik (or actually do it). The turnip pull was bad because you lost time doing it that you could've used getting the ledge.
26:35 I don't like that downsmash there. I would've preferred that you upsmashed...but it worked, I suppose. Upsmash would've gotten you more percent than the downsmash did, and a better position vs Sheik.
26:37 Why are you using dair there? He jumped in the perfect uair position, but that's a hard read. Still, you could've naired/baired for a possible trade. Dair...doesn't really do anything. Not from that angle.
26:44 This was good. You jumped back and avoided his fair. Then you were able to establish a float. Then you punished his FJ (well, more like his landing) with a dash attack, which gave you good damage + positioning. I wish you'd uaired after the dash attack, but that's fine.
26:51 Bad downsmash. An aerial to send him off would've been so much better here.
26:55 You got baired because you moved in. And then you get sent offstage because you're holding in. I think you had a float there (not your DJ though). You can't float while in tumble. Wiggle your analog stick (or use toad) to get out of tumble, then float. It's VERY useful for recovering, because you aren't forced to use your upB just because you're in tumble.
27:02 Backjump would've been good here. With all of your recovery options online, I think retreating offstage in this situation is alright (I think shielding there was much worse, and I don't think you were in the percent range to CC Sheik's ftilt).
Recovering vs Sheik is about patience. Recognizing when she can bair/needle you and avoiding those at all costs, recognizing when she has to wait for you...I feel like, often times, you don't have any choice but to go extremely high or to the ledge, since she punishes airdodges very well. But take your time when recovering. Try not to take critical hits/damage (please watch out for her uair, it kills earlier than you would expect. Or at least treat it like it does).
27:14 This is a habit I get into often...trying to attack people as I'm recovering. It is way more important to get back to the stage than it is to try to hit them. Sometimes you'll get the hit...but sometimes you'll whiff and possibly die (even if it takes a while because Peach).
You seem to be doing a good job of punishing his landings from FJ with dash attack, btw. Good stuff.
27:25 It was good...but then you didn't grab the ledge. You don't always need a veggie to edgeguard. Remember that.
27:30
27:39 You should have just grabbed him. Downsmash wouldn't do what you wanted to do at that point any better, and it had more of a chance of failing, because of shield.
27:47 I don't agree with trying to fair over him at all. It left you far too vulnerable. You don't normally want to pass over Sheik like that (only exception is maybe if she's shielding).
27:49 Floating that low vs Sheik isn't bad....until you're appraching her with it. Which you were. Actually, it's fairly bad if she's not shielding because needles are good against that height unless you're really close to her.
You lost your 3rd stock by trying to be too aggressive offstage again. Whenever you moved forward, you got needled, or hit.
28:20 Another instance where backjump would've been a lot better. You just jumped into his needles, and then got comboed for 28%.
28:23 You've done this quite a bit, and I need to point it out here, because it's something a lot of Peaches do. It's a bad habit that we sometimes get away with because people are bad. But it is still BAD. Don't downsmash when someone isn't near you. Just don't. Especially not from the top platform like that, because it is easily punished.
28:32 After knocking him off that time, you should have grabbed the ledge. Something else you need to work on, you don't grab the ledge enough when you can. You often pull turnips, which costs you the edgeguard (or you set yourself up improperly).
28:36 You could have dash attacked that bair, rather than just running into it.
28:42 It was a bad place to jump vs invincible Sheik, especially with a turnip. Be more mindful of when your opponent has invincibility, and how you can avoid it/use it against them.
If you watch the rest of game 1, it's basically more of what I mean. You get too aggressive, you want to move into Sheik too much, and you get punished for it. So if I could tl;dr this for you...
Work on your mobility vs Sheik. It's very important. Also work on your techskill in general (I know I told you this last time, and it would've been much more relevant had I done this on time >_> ). Your edgeguarding is pretty weak vs her...I'd suggest watching some Armada vs Amsah, or Armada vs Overtriforce, and look at how he edgeguards them (treat the rest of the sets with caution, because they're PAL and the MU is kind of different there). Pulling turnips can give you an advantage, but also lose you time. Be prudent in choosing when to pull them. You move into Sheik too much. This is bad because Sheik is good at stuffing our approaches, and it's also bad because when you approach (or move into your opponent), you're automatically DI'ing inwards, which is TERRIBLE DI if Sheik wants to combo you (which reminds me, DI her moves away, except for fair at high percent). You could work a bit on comboing her (something I didn't really talk about). From like 35-65, uair is an amazing combo move on her. Don't fish for it, but use it when you can.. Dtilt sets up for a lot of good rising uair/FC uairs (which brings me back to practice. Practice your Sheik combos, learn percents [even if CPUs don't DI properly, you can eyeball ballpark percents for when things should connect, and then test these ranges in friendlies, and adjust your findings according], and practice float cancels).
Again, I'm sorry this is so late. It just got away from me. If you've any questions/comments/complaints, feel free to shoot.