Yo Scar.......Shiek
she's gay, I'm good if I use Falco
but...
i'd rather **** her with Falco + N
sheik is really gay, watch
me vs plank, try to learn as much as you can from that but i really don't have the matchup perfectly
get those edgeguards that i missed, get those uthrow knees that i miss, but the real hard part of the matchup is getting those hits in and punishing hard
marth and sheik are two matchups that you can only win if you have a solid offense. they are going to hit you more than you hit them, your only saving grace is that you are heavy and hard to kill (don't DI in vs ftilt @ like 90 though bc you have no chance of surviving that lol), and that you aren't combod AS EASILY as them
that said they **** you hard from grabs and they have a tendency to have long, drawn out, damage-dealing links that will hurt
spacing nairs is not as effective here as maybe vs fox and falco and low tiers, what's going to do more for you is using your superior maneuverability and picking your spots better than they pick theirs. work the platforms to your advantage vs sheik, stay away from yoshi's story vs marth (dtilt and tipper hurts too much, let them take you to fountain, seriously)
keep at it and you'll be okay, watch me, watch darkrain, watch hax, watch nes n00b, watch bigD, watch SS, and just take whatever you can that you think is smart
but don't just look and be like **** i wish i could do that or **** that was ****, look for LITTLE things that other people don't notice and figure out why it works or how you can use it or how you can make it even better
also watch vids of yourself and find out what you're doing wrong