How do you get close to a girl when you've liked her for a while etc

So pretty much the topic explains most of it. I like a girl and have done since first year of uni, I had a chance to get with her but my mate liked her and I got out of the way at my own expense like an idiot. I defo think she fancied me, she had that look on her eyes. I still talk on facebook comments a fair bit but never chat and if I see her round uni it's really nice, she seems to have a twinkle of interest but I can't tell if its actual or not, on facebook its quite strange because when I comment or she comments it doesnt feel like she's saying these things as a mate and it feels kind of like she might like me sometimes. Only problem is I've known her a long time and it's quite difficult to find a social situation to make it not awkward or suggest I might like her without seeming to be coming onto her randomly. So what do I do?