I'm a pretty shy guy around girls. Recently I had to ask someone out for the first time, so that I didn't go insane (she was all I could think of!).
I find that it's a lot easier rather than talk to her face-to-face, to put your feelings into writing, whether it be email, post or SMS text message. this way if everything goes wrong, (which it probably won't), you're not going to be left standing there unsure of what to do. Admittedly the reply takes a little longer, but for me (I sent email) it worked just how I wanted it to. Now I need my post answering about what to do next.