I actually posted this in another Sheik help thread so this should technically be in quote form, but I personally don't like reading it in quote form so here it is:
Ok Sheik you say? lol haha every yLink main has trouble playing Sheik their first couple times but through EXPERIENCE and smart thinking, the matchup can be overcome and personally Sheik is a comfortable matchup ^_^
NOTE: SHEIK IS STILL A REALLY GAY CHARACHTER AND CAN **** YOUNG LINK HARD
O.k. here we go
First of all, we prolly are going to talk about stage selection. There really is no "best" level to play Sheik, but there are quite a bit of stages that she can screw around with young Link pretty bad (i.e. FD). Good levels to fight Sheik are probably PS, this is because the stage is LARGE with PLATFORMS as well so chaingrabbing won't be as likely. Following the same, distorted patterns of PS will prove in your advantage because of the spam-advantage qualities when the stage changes (such as the mountain stage with the HUGE mountain that can help you spam from high above, or the big, burnt tree which you can use as a big dividing line between you and your opponent and space your projectiles AND can use the tree for a quick, invincible escape if they come your way so you both swap sides [in case you didn't know, you're slightly invincible between wall-jumping, sooooo that basically means that if they see you coming their way and the Sheik tries slapping you with a fair, then you can wall-jump and double jump to swap sides =p). And battlefield is also pretty helpful for young Link because of it's neutral qualities. FD is NOT good obviously because she can chaingrab you ( Ooo but there is a special-super-duper DI trick that can get you OUT of CHAINGRABBING =D ). Anyway, DL is so-and-so but prolly in Sheik's slight advantage though. Uhh same with YS and FoD too.
Okay on to the matchup. At the beginning of the match you must spam. All in all, you must work on your spam game; know when to use which projectiles at what times. Take a bomb out and throw you boomerang first. You see, at the beginning at the match your just trying to space yourself against Sheik before you unleash a combo starter. To start off your first combo, try and land a bomb on her. From there, the best combo is to land a PBB (Point-Blank Boomerang which will do 19%), or you can do an upsmash (The Jash Combo :] ) or a utilt, uair, or whatever to start up a combo. If your feeling like a real wuss you can go for a simple nair or dash attack to get her away from you
Aight, so the first part of the battle is spacing yourself so you DO NOT get grabbed but it will happen eventually. Sheik is looking for ANY oppurtunities or openings to get you. So her counter to your spam is spamming back with her needles of course. Let it be known that your projectiles is > than her needles but it is still VERY close. Alternate from spamming on the ground to spamming on the platforms to spamming from above her, then retreat. The Sheik (if it's any good) will soon realize that needles won't do the trick so this is where Sheik will get clever. She'll probably use wavelanding on platforms and fastfalling to squeeze through your projectile gaps and eat you up and believe me: that strategy works. The Sheik will sometimes just skip the whole spamming back part and go straight to tryin to get ya.
If Sheik gets near your face, try spacing SHFFL'd fairs against her ( best way is by using the C-stick and DI'ing backwards for maximum spacing) or use jabs too if she's close. When she gets close to you, attempt to get her in her sheild by spacing fairs, nairs, jabs, or anything with little lag but good range so she doesn't sheild grab you. Sheik will proabably approach with an arial or dash attack, tilts, grab, or any other aggressive nature attack (duh!) so spacing with the Fairs, nairs, and jabs is useful in not getting grabbed.
What's that you ask? Sheik doesn't JUST try to get grabs either? Oh yeah Sheik has the "gay" tilt comboes too. Well, if Sheik DOES try to start some comboes with tilts then you must Crouch-Cancel them darn tilts! >=[ You'll have enough time to see the f-tilt coming out to CC it so you don't get comboed (keep as a reminder that this is still the beginning of the match and that the CC works only when you're at low percents), but if the first tilt hits you still, then no problem, all you got to do is DI down and from the tilt's trajectory and you'll land on the ground back in CC position.Crouch-Canceling is crucial in defeating Sheik. Now, once you have successfully CC'd the tilt, now you must act! There are several things you can do once you CC'd; this is because Sheik is open to lag during her tilt duration (forward, up, or down, but most commonly forward). My personal favorite move to do in CC position is the D-smash because this will hit her away from you, thus no comboz no more, and at moderate percents it will hit her off the stage or hit her onto the edge. Hitting her away is good, because it keeps Sheik on the defense which gives you time to spam at her when she's away. ANOTHER technique you can do is d-tilt. The d-tilt is better to use if you want to set up another combo on Sheik such as d-tilt -> u-tilt-> uair uair uair = ****. The only problem with this is that the d-tilt is slow when it comes out and is slower than the D-smash (d-tilt comes out at 14 frames; D-smash comes out at 9 frames) so the Sheik may have time to put up her sheild after her tilt so she sheild grabs you before your d-tilt hits her. So the D-smash may seem more safe in situations. Another move you can use is upB because it's fast (an attack that comes out at 8 frames) but D-smash and d-tilt seem more practical IMO. Now, if the Sheik is good then it'll realize that you're going to attack in your CC after her tilt. If you were unsucessful then the Sheik will have time to act before you do (which is unlikely) so she'll probably use D-smash or sidestep dodge. Just sheild in your CC to block the D-smash or sheild grab after her sidestep dodge. But remember, Sheik won't usually have time to act after your CC counter attack.
Remember that you DI tilts away from Sheik and to DI her Fair up with the contol stick and toward the stage with the C-stick.
Alright, now you get Sheik up to a high percentage through good spammage, spacing, comboing, and good defense, but you need to hit her off the edge now. The best way is to either land a D-smash on her or do a bomb-> nair at her. A SHFFL'd Nair after the bomb is probably the most reliable way to hit her off the edge, which will NOT kill her if your opponent knows how to DI, so the way you kill her is from some sweet edgeguarding >=].
Ok, when Sheik is AWAY from the ledge and is recovering, try to attempt to jump OFF the edge and nair her and upB back to the edge so she dies early by not being able to reach the edge just in time. If she does come back to the stage, do ledge-hop -> Dair on her because of her horrendous lag after her upB.
BUT let's say you DIDN'TTHINK YOU HAD ENOUGH TIME to jump out and nair her before she upB'd and become invincible. Instead just throw a bomb out at her, but NOT to actually hit her. The bomb will act as a distraction and force Sheik to upB as early as possible back to the edge, giving you control over her upB and edge-hogging before her (since you forced her to upB when you wanted her to). But if the bomb DOES hit her then whoop-ee, jump out and nair her during the bomb stun. Now, while you're edge-hogging, it'll be wise to ledge-hop stall for invinciblity frames (since she's invincible during her upB but can hurt you still). If you are succusful with your ledge-stalls, then you will force Sheik to land on the stage with her lag, which gives you oppurtunity to ledge-hop Dair her (mentioned above already). If she lands on the platform above you, then ledge-hop Uair and combo her with more Uairs. If you are unsuccesful with your ledge stalls and you have to roll back up then Sheik will grab the edge again. At this point, the only thing you can do is throw bombs at her while she ledge stalls ( Sheik has freakin' amazing ledge stalls O_O) and if you get too close she'll quickly ledge-hop and slap you in the face with a Fair, so watch out!
Now how do you recover against Sheik? Well remember to DI her Fair up and toward the stage. Uhhm... remember to throw bombs at Sheik while you're in the air if she plans to edge-hog you and then jump out and bair (it's **** on young Link, trust me) but the bombs will do the trick, because Sheik will either get hit by the bomb or she has to roll onto the stage and let you get back on to the stage. If Sheik is needle spam edgeguarding you, then air-dodge and hookshot the edge. If you're upBing under the stage remember to Ledge-Tech her d-tilt -> Fair or just a plain old D-smash.
Alright here is the Super -secret DI trick in which my brother and I discovered with young Link and Link! I would've wrote it myself, but I felt my brother here wrote it nicely himself on the Link boards =). Remember it's ONLY a mindset in which makes you APPEAR like you are behind Sheik when your really like in front........... it's confusing but you'll get it hopefully:
Just to let you know, here are some good Sheiks that I've faced before:
I've faced SlyD (is the 3rd best Sheik in Washington), Ka-master (just in some friendlies), Hitsuguya of Canada (is ranked 1st in B.C. Canada), and Dieslow (ranked 5th or so in B.C.)
Anyway, I hope I helped out a lot after that ridiculously long post =)
There you go ^_^