Well, when I was younger, I just ignored it. I didn't stand a chance with the person in question, it was just me wanting what I couldn't have, and not even being aware of what I truly wanted anyway. It was a meaningless hormone thing, so I shrugged it off.
These days, it'd be impossible for me to develop a crush on someone. I don't really care about physical appearance, and nobody would get close enough to me to the point that I would even consider romantic attraction to them, because...reasons.