Add something they could not get from the original
Commentary, criticism, and teaching are the usual hopes. Playing the whole movie while you nod is not. Use the smallest piece you need, talk over it with a real point, and be ready for the platform to side with the rights holder anyway. Fair use is decided case by case, often in a country that is not yours.
If the video only works because of someone else’s footage, assume you need a license or a different idea. This page cannot clear your upload.