How do you find out if a guy really likes you when you know that you like him?

Like some guys I'm terrible at picking up on clues and signs when a girl is interested in me. I've been told to see if she finds an excuse to touch you in conversation or see if she smiles alot, blushes and her eyes dilute. Personally I think the best way is to just go out and ask him believe me if girls did that to me I'd find asking girls out alot easier.