What are some good ways to look around and see if someone likes you?

To Answer your question regarding the catching girls staring at you, it's nothing but luck, this girl that I like seemed to be staring at me during my entire third period on the first day of school, I only caught her by chance. Some other ways, if she keeps asking you about yourself, seems to want to be close to you, or seems nervous around you ( of course that last one could mean that you just make her uncomfortable), try talking to her, the worst thing she can do is say no.