The only way for this is to step outside of the 'shy zone'. There is really no way to stay comfortably shy and get a guy to notice you both, unless he notices you to begin with. You really just have to put yourself out there, and this can be difficult even for people who aren't shy.
You really have to treat him a bit different than you do others. You have to be a little more pushy, not in a bad way. But make effort to be around him more, maybe try to sit next to him. Be a little flirty, put yourself out there and, to be honest, be a little vulnerable. Anyone who steps out to get another persons attention, or ask them out or whatever, is taking a risk and making themselves vulnerable because there is always the chance of rejection.
If you want to get his attention you have to step outside of the shyness and be a little bold.