Emotions are like wild animals, aren't they? Very hard to tame. since you know that having those feelings for him isn't beneficial for you, it's really important that you learn to control those emotions. The trick is to remember that our emotions are formed by the thoughts we think. If I think, "Wow, he's so cute," or "He's like the perfect guy," or "Maybe he really does like me, but just doesn't know how to show it," what sort of emotions are going to follow?
Obviously, if you're thinking about him a lot, you're not going to be able to get rid of those "crush" feelings. How can you stop thinking about him? Well, that's completely up to you. I'd advise to steer clear of him whenever possible, at least until you get your emotions under control. If you're tempted to day-dream about him before you go to sleep at night, pull out your Bible and spend some time fixing your thoughts on God instead, focusing on becoming more like Christ instead of becoming whatever you think this guy wants in a girl.
This passage from Philippians is a good one to memorize and meditate on when you feel your thoughts begin to wander toward him:

Don't fret or worry. Instead of worrying, pray. Let petitions and praises shape your worries into prayers, letting God know your concerns.
Before you know it, a sense of God's wholeness, everything coming together for good, will come and settle you down. It's wonderful what happens when Christ displaces worry at the center of your life.
Summing it all up, friends, I'd say you'll do best by filling your minds and meditating on things true, noble, reputable, authentic, compelling, gracious--the best, not the worst; the beautiful, not the ugly; things to praise, not things to curse.
Put into practice what you learned from me, what you heard and saw and realized. Do that, and God, who makes everything work together, will work you into his most excellent harmonies.

Philippians 4:6-9 (The Message)

Best of luck, sis!

Love,