I'm a coward... How can I tell her...?

I really like this girl and we talk at school a lot but I still fear rejection... I can't come up with any reason to do ask her out... I'm no looker and not athletic... I don't know what to do... I can't just say it... Fear is a powerful emotion... My friends make it sound so easy... It's like everytime I see her... I feel awesome... As she goes I'm left with nothing more than apathy... I'm not sure what to do...