What does it mean when your ex turned his head to your direction to stare at you-does he have feelings?

I sit next to or near my ex-boyfriend in most of my classes, and sometimes I'll peek out of the corner of my eye and see him staring at me. It's been a year since we broke up, but sometimes I feel like he still has feelings for me. I try to look for these signs:
1.) If he just stares at you once it really doesn't mean anything big. If you see him staring at you a lot, just ignore the first few stares, and after awhile, smile at him. Boys get embarrassed when they see a girl smile at them after getting caught staring at them.
2.) If he talks to you regularly, or even a lot, that may be a sign that he still likes you. If he says things to you like "You look pretty today," or "Can I walk you to your next class?" or any other flirty comments, he may still have feelings for you.
3.) If he is flirting with you, watch him with other girls just to make sure he isn't flirtatious like that with all girls.

Then follow this:

1.) Talk to some of his close friends and see if he talks about you.
2.) Talk to him and talk about your breakup and where you two went wrong.
3.) If his flirtatious behavior continues, he most likely has feelings for you still. Ask him calmly one day when it's just you two talking, not around your friends or his, ask if he still likes you enough to be his girlfriend again. If he says yes, then congratulations! If he says no, don't beat yourself, he could be lying because he might be embarrassed, or he may just want to be your friend. If he does say no, just say something like "Oh, I was just wondering. I think it's best we're friends too."