Sooner or later you need to let your crush in on your feelings if you want to have any hope of taking your attraction from fantasy to reality. I suspect you know this. You need to be the one to share your feelings with him, not a well-meaning friend. (Read some of the many other questions, and you'll see why I recommend against having a friend get involved in telling your crush about your attraction. There are so many things that can go wrong.)
You have to work up the nerve over time to let him know you like him. Start looking his way and smiling. See if he returns your attention. Try to have small conversations with him, sit closer to him in class or at lunch. See if you can connect with him over social media. As your contact with him becomes more frequent, you'll become more comfortable. Throughout this process, pay attention to his nonverbals regarding whether he's flirting back with you. Good luck.