What should you do if you like a guy and you hardly get to see or talk to him but you really want to come up to him to talk to him but you know that that would be awkward?

Fear is one of the hardest things to overcome. It is a mindset issue. One day when you see him, you have to mentally tell yourself "I'm going to go talk to him." Start the conversation with a compliment. If he is even the slightest bit interested, he will compliment you back. After that, the conversation should be easy. The hardest thing is getting that mental mindset.