Shooting lasers definitely makes Sheik's life into a living Hell, especially if she wants to dash/run at all. Low lasers beat her run (very low profile) clean, so be sure to have control over them. If she tries to do basically anything but dsmash (stupid, but happens) or grab before... ~45%, just CC it and punish from there. If she wants to grab you for shielding, fadeaway dair OoS is actually amazing. If she's above you, a well-timed utilt beats quite literally everything she can throw out.
If/when she gets that one grab, use DI and techs to test her skills to the max. DI one way and tech the other, DI out and tech in place, DI one way and tech that way, DI behind and wakeup shine, any DI + missed tech getup attack, etc are all amazing things to consciously mix up with each other. If they can perfectly techchase every time even as you mix all these things up, I daresay they deserve the stock. Also, they're almost never gonna dsmash/fair you directly out of the tecchchase. You'll very often see them ftilt or dash attack into fair. Hard DI out from the DA/ftilt will make the fair way harder to hit, if it's possible at all. DI in if they DA at a time where only the back portion will hit you (becomes instinct). As one last thing, I know this is just survival DI basics, but you really do get so much out of DIing up and in vs her fair.