• Check out school events: that's a good chance to meet him.
• Investigate who knows him. You can do that at school, or check facebook. If you know an intermediate you can find ways of meeting him outside of school.
• Be somewhat more persistent with what you have now: You meet him several times a day, each day, you are bound to find chances of meeting him. Some days of the week may be better than others.

But mostly try to overcome your shyness and behave naturally,... Your initial aim should only be to make contact, and then you can progress from there.