I used to have this crush but I lost all respect for him because he basically ignored me for ages and talked to me like nothing happened, and our talking terms were on and off, and he acted like nothing happened.
So I lost my crush for him. Also, he's become much less attractive now anyway.
Even if we did have a chemistry like before, I'm transgender and he's NOT gay. And it would be long distance. So that wouldn't work.
But oh well, I don't need him. I'm fine.
Anyway, when it comes to YOU getting over a crush... I dunno.
What about trying to find as many flaws/dealbreakers as possible? I'm no good with this, my crushes and my interests are two different things. To me, a crush and a love are very rarely collocated, you're lucky if it is. Unless that's just me being weird.
But anyway, just try and see some awful things about her/him, or if not, just find someone better. Easier said than done, but I wish you good luck.