I'm a shy girl...how can I flirt more obviously, without looking desperate??? Guys...what do you like?

My guy friend and I may kinda like each other. He told me "girls should be more straightforward. It would be so much easier". I think he was trying to tell me I am giving mixed signals. I thought I was flirting fine! What can I do to make it more obvious? I'm shy & so is he. He has never laid a finger on me...literally! Suggestions plz!!!