Any tips with SHFFLing u-Air? I tend to tilt it too high and double-jump most of the time.
Also, even though I've read the sticky, are there any tips against Peach players? Namely one who likes D-Smashing a lot.
As far as shffling uairs, sounds like you're not using the c-stick. Use the c-stick. It's important.
Now, as far as Peach goes. She tends to love the stick, if you know what I mean .... >_>'. I usually space with bairs, and full jump dairs a lot. Pill approach is nice but it can be countered with float/float-cancelled bairs or nairs. Usually you want to space with bairs, ftilts, fairs, utilts and come down from the air with uairs. Usually when I land a grab on her I'll do something along the lines of the following:
1.) 0%, grab, dthrow, full jump dair (she can nair out of this if she knows what she's doing)
2.) 35%, dthrow sh uair to see if I can shffl her with some uairs and juggle her until I can land a finisher or something (depending on the situation).
3.) 85 - 100%, dthrow, full jump fair (following DI).
Yeah usually when you grab her at around 90%, you can dthrow her to full jump fair which will most likely kill her. Just make sure you follow her DI since (if she knows what she's doing) she will probably try and DI behind you.
When you see her camping on a platform, don't go near her unless you can reach her with the highest tip of your utilt. Even then it's just overall safe to stay away from her and pill-spam (correctly).
Another thing I'd suggest doing is banning Mute City as a counterpick. Terrible stage to fight Peach on. If you do that though, beware of Dreamland 64 and Kongo Jungle (the level with terrible edges, like a 1000 X worse than Battlefield).
If you land the first part of the nair on her when she's around 90%, I'm pretty sure she'll be sent in range of a full-jump fair.
Hope that helps.