Thor
Smash Champion
Sheik is dumb, her ftilt is am especially silly move. Bait it out though, Sonic goes fast.
It's probably better to just DI dash attack away, you can CC it to pretty high percents but once you get high enough percent, a CC will probably still let Sheik dash attack launch you and then you get KO'd by the timeless combo dash attack -> fair.
For the "You should know" portion: Sheik dthrow is a DI mixup with Sheik bthrow - while you usually hold away (and down) for dthrow, you also hold away and down for bthrow, BUT bthrow goes the opposite direction (so actually toward Sheik prior to the throw). The PMBR made this ~16 frames to try to make it unreactable - some humans CAN react to this [though I'd imagine doing so for extended periods is still difficult, as few humans have that quick a reaction speed), but one trick is to hold down whenever grabbed and then from there try to guess which throw is likely and DI that way. IF you DI such that you have the "right DI" you'll go far away [but can be set up for edgeguards because Sheik is dumb], but if you do not you'll be in a prime position to be regrabbed. As a Link main, I have also seen bthrow -> DACUS because I did was expecting dthrow (and was holding just away from Sheik, so what ended up being DIing in), and the DACUS tippered and KO'd me. I think that works on Sonic as well, at least at certain percents.
I read the Marth tips, and I have a few suggestions for things to change if the OP is willing to listen...
It's probably better to just DI dash attack away, you can CC it to pretty high percents but once you get high enough percent, a CC will probably still let Sheik dash attack launch you and then you get KO'd by the timeless combo dash attack -> fair.
For the "You should know" portion: Sheik dthrow is a DI mixup with Sheik bthrow - while you usually hold away (and down) for dthrow, you also hold away and down for bthrow, BUT bthrow goes the opposite direction (so actually toward Sheik prior to the throw). The PMBR made this ~16 frames to try to make it unreactable - some humans CAN react to this [though I'd imagine doing so for extended periods is still difficult, as few humans have that quick a reaction speed), but one trick is to hold down whenever grabbed and then from there try to guess which throw is likely and DI that way. IF you DI such that you have the "right DI" you'll go far away [but can be set up for edgeguards because Sheik is dumb], but if you do not you'll be in a prime position to be regrabbed. As a Link main, I have also seen bthrow -> DACUS because I did was expecting dthrow (and was holding just away from Sheik, so what ended up being DIing in), and the DACUS tippered and KO'd me. I think that works on Sonic as well, at least at certain percents.
I read the Marth tips, and I have a few suggestions for things to change if the OP is willing to listen...
If Marth runs at someone, his 3 most likely options are dtilt, grab, and wavedash. Marth can crouch out of a run (not initial dash, but a run), and dtilt and grab are soooo much better than dash attack (which is slow and laggy). A Marth that is DDing will likely either keep DDing to bait something, wavedash -> dtilt/fsmash (fsmash riskier but some get greedy at KO percents or read a jump in, and fsmash beats jump in handily), or a grab. And Marth's really love grab because they have gigantic grab range and solid throws for positional advantage. Marth should also be able to fthrow CG Sonic at least on bad DI - DI away (also if you DI in you can be fsmashed for it).
Don't always tech in place - Marth can just regrab a tech in place. While it may generally be the best option, if you don't mix it up the Marth will just take every single free regrab, and that's a problem for Sonic.
Marth can short-hop fast-fall a nair and he does not need to L-cancel it [it autocancels]. As a result, SHFF nair is actually somewhat trickier to punish than one would think. However, if he does late nair, that does need to be L-cancelled.
Don't always tech in place - Marth can just regrab a tech in place. While it may generally be the best option, if you don't mix it up the Marth will just take every single free regrab, and that's a problem for Sonic.
Marth can short-hop fast-fall a nair and he does not need to L-cancel it [it autocancels]. As a result, SHFF nair is actually somewhat trickier to punish than one would think. However, if he does late nair, that does need to be L-cancelled.