First, you have to be willing to lose her as a friend. You ready? If so read on.
Second, you have to have the balls to let her know that you want more than a friendship. If you don't, just leave now. Remember, you are already willing to lose her as a friend, why not have the balls to try to make her more?
Okay, so you have the Intent. YOu have the Balls. Your halfway there. You know how you and her will pal around and just go and play video games/walk around/ whatever? Yeah that is what I call the "Pal Routine". You need to break your pal routine with her. Go somewhere you have never been together and then act how you normally act except you begin Kino. The difference between friends and lovers is 3 things. Intent, Kino, and SOI. As I have said you already Intent. You must establish and escalate Kino and then make a SOI. An SOI is a Statement of Intent. This tells her that YOU think of her in a different way than Bob your friend from the village. But Evo... What are some examples of SOI's. Well billy, they are as follows:
"I really want more from us than a friendship."
"We deserve to give US a chance as more before we settle into this friendship."
"I like you more than a friend."
"You make a terrible friend... but I think you would do much better as a girlfriend. Maybe."
You KNOW what SOI's are. You have probably been telling yourself one about her over and over and over inside your head.

(Just so you know... certain Kino can be considered a SOI. LIke touching in her nono-spots or kissing her. This should be used cautiously though and APPROPRIATELY.)
So. Now you know all the 3 steps. Intent, Kino, SOI. Intent is Change. Kino must be escalated. SOI's must be clear.
Goodluck
EvoJ