How can I get this girl to notice me?

OK first of all I'm sort of a shy guy but I still have many friends that are girls and normally I don't try to be friend but we share the same ideas so we just start to be friends but anyways. I want a girl in my homeroom to notice but it's like I get punched in the stomach every time I try to talk to her. When I do get time to talk to her she is very friendly to me but that can mean anything, not necessarily she likes me. so how can I get her to notice me with out making myself look like a weirdo.