About the glasses that let you See. If you made small spectacles, you could always glance over top of them to see the normal world. Sometimes the Fair Folk want to be seen (boys with frog eyes and girls with hollow backs) so looking at those Fair Folk could potentially get you in less trouble. If they ask about you staring, you could say they fascinate you (truth) without revealing that you can see their true form. And things you shouldn't see at all, you don't look at for too long.
They’re all got tells; no glamour is flawless, however much they might want to look like us for a time. If they want to be seen, you’ll know. If they don’t want to be seen, you’ll also know, in pretty short order.
But yes - if they don’t yet know you’ve stolen the Sight for a time, flattery is absolutely the way to go if you’re hoping to keep your eyeballs. Lay it on thick.