Coming from a shy guy who is terrible at expressing himself...
- He will avoid contact at all costs.
- He'll Admire from afar, cheeky little looks and stuff.
- He probably thinks you're out of his league.
- Initially he will give short answers to any questions you have.
(he will loosen up over time hopefully)
- I'm 95% sure he will NOT make the first move.
This means that you should go and talk to him.
Shy guys feel REALLY flattered if any girl goes out of her way to talk or to initiate.
If he sits by himself, sit beside him one day in class.
If you're the type of girl that has a big group of friends then he will definitely feel intimidated by that.
Try and catch him by himself in a 1-1 basis.
Take interest in him, and compliment him - it will go a LONG WAY.
Finally, be consistent with him. Take interest in him when you see him.
Don't talk to him one day and then ignore him the next.
Keep the contact level high and he will loosen up eventually.
Shy guys have barriers, you just need to get past it.
Hope this helps!