The first step of this process is rather quite simple; get her attention.
Initiating conversation is half the battle. As well, it is very effective to make frequent eye contact.
If you tend to fall into the "friend zone," this will be especially important. Real girls (girls with a strong sense of purpose and self-worth) don't like guys who have no lives or who cling to them like plastic wrap .
Some girls do like that, but for all the wrong reasons—either they're insecure and needy for attention, or they're control freaks who have a need for dominating guys. Unless you want to sign up for one of those scenarios, focus filling your time with your own friendships, interests, hobbies, and goals. This also gives her a chance to do something with you without it becoming a date.