I'll tell you what always worked for me, and I was always with the most popular and cute guys.
Most of the guys I would just catch their eye, kinda like from the side like a staring glance, I mean don't stare for a long time, then just turn away and smile. Do this once a day every time you see him. That usually catches their attention. They usually come up to you after that.
I did this one valentines day, I decided to try it, so I went to the track field and all the track boys were running, I was standing next to my coach and other people and one of the guys that was running I made eye contact with as he ran past me then the second time I smiled and every time he passed by while running I would smile coyly. Kinda like a shy smile, while making eye contact. And every time he passed by he would look at me and smile. Then on valentines day, he sent me a teddy bear and asked me out!!