my social butterfly mother taught me about a "fake-ness" that's worked well for me in situations like this: when you talk to them, follow every opportunity that reveals something about themselves (eg "you mentioned that you liked the color blue, i kinda like it too because of X, why do you like it?") and do it even if it bores you and you grasp at straw to keep the conversation going. people love talking about themselves and love it even more with an audience that seems into it and, at the end, either your crush will be dispelled or now your crush is aware of you.

if they act odd after that; then they don't feel the same way about you that you feel about them and move on. if they do feel the same way about you OR if they don't, but they still like you; they'll likewise look for an excuse to tell you more about themselves.