If he's getting predictable (always dtilting after he fairs your shield) you should be able to throw him off by buffering a spot dodge or roll when he thinks you'll go for the grab. And always try to DI away if you think the dtilt may hit you, so that she actually has to work somewhat to get a decent combo on you. Try to play just as gay as the sheik is; don't always feel like you're the one that has to attack. Remember how important the ground game is, as Tipman said, and use your aerials (uair and bair mainly) to keep pressure on her.
A good bit of this matchup is centered around winning exchanges (moreso than most other matchups). If Ganon gets hit, the consequences can be devastating.. but basically the same thing goes for sheik. This is why moves like jab, uair, ftilt, and bair are so important; they are faster and have a good amount of range. AS TEMPTING AS IT CAN BE to go for that killer dair > grab, with sheik it's often better to stick to your safest options. I wish we could play some dude