Your best option is to get a girlfriend once she sees you with another girl she's gunna see you as boyfriend material . That's how girls work .
Another thing you could do is tell her how you feel , who cares if she doesn't feel the same and the friendship ends . it's better to get rejected then being secretly in love with her forever .
The last thing you can do is get out the friendzone which is the hardest thing to do , some people say it's impossible only few guys have done it . The way you could is give her hints that you like her ,flirt with her . Make her get used to you flirting with her . You could also act different , don't return her calls right away or text her back right just don't act like you usually do .
There's a lot of other small things you can do but that's a start , good luck man. Oh and another thing the longer you wait to make a move the worse it's going to get your going to get deeper in the friendzone or even worse she light get a boyfriend and that's gunna hurt you bad .