BASICS OF SHEIK VS SPACE ANIMALS
STUFF TO TRY AND GET AT LOW PERCENT
If they're almost anywhere - short hop aerial (needles count) > grab > down throw > stuff
If they're directly above you - u-tilt > grab (or more u-tilt) > down throw > stuff
STUFF TO TRY AND GET AT EVERY OTHER PERCENT
If they're almost anywhere - short hop aerial (needles count) > dash attack or f-tilt > stuff
If they're approaching you with SH - WD back f-tilt / d-tilt > u-tilt or other combo moves > stuff
If they're approaching you with FJ - short hop bair or fair > dash attack > stuff
THE SHIELD GAME
Learn how to Nair OOS and WD OOS (generally you'll do these after the shine). Sometimes just sit in shield during pressure to see if they'll do a high aerial. If they do, and they don't retreat, grab them (aerial OOS if they cross you up). If they high aerial and they retreat like they're supposed to, WD back OOS. Mixing between these three is a good start.
Block and then WD back (before you get hit in block) if they seem to be aiming their aerials, grabs, or other moves at where you are (as opposed to where you're going to be). By doing so, you can make them miss (you can see Samus players do this a lot) and then get a free grab (and various other moves). It's a reasonable trick.
Rolling is sometimes okay, sidestep is sometimes okay.
CAMPING OR APPROACHING
If you camp, at least do it right. Make sure you have enough space to WD back so you can actually defend against most approaches. Basics of camping are you're gonna try and make a defense strategy that's only answered in a few ways (ideally it beats how they're initially approaching you). Remember that simple is better. If it involves more than two moves you've made it too complicated. They will eventually come up with the counter to this strategy, at which point you use something that answers their counter. Then you just play numbers, or choose your play based on what they're doing.
If they make you approach, just move towards them and see if you can catch them lasering poorly. Knowing how you can control where Falco shoots lasers is good here. If they are good at lasering and stop on time, then see if you can scare them into running towards you by inching into their space. If not, move closer and see if they'll panic. Your goal is to cut off options and get something substantial. Namely grab. Pay attention to the ranges where they start to attack out of panic or move around out of panic and try to come up with a decent strategy to cover those options. Remember that simple is better, and ideally it involves something you can combo off of.
Grab is better than dash attack against stationary opponents because it goes through block.
edit:
Obviously there is more to all of this than that, but that's the simplest way to think about Sheik vs space animals when you're starting IMO.
