Easiest way to lose friends?

Well, I have this friend. Let's say her name is Shelly. We were good friends in elementary school but now, she acts like she gets really annoyed with me. Shelly has a ditzy personality where she always acts dumb and over laughs. She always wants to hang out like a big group but whenever we do, if I try to get her attention, she holds her hand literally an inch away from my face and says "she's busy". Whenever she wants to get my attention to borrow something, though, she would snap in front of my face. Not only do I find this rude, but I think its gross because her hands are not very clean. During cl, she would talk to her boyfriend when the teacher is speaking and text during cl. Last week, I went to her church camp with her and while waiting to perform a skit, I asked another friend if I should say a line or not. Then, Shelly rolled her eyes and shhhhh'ed me and acted really interested in the skit before us. The, a minute later, Shelly started talking to another girl about Shelly's hair. This makes me fell like a little kid, to be shushed like that. And that wasn't the first time either. Shelly takes at least 3 pictures a week of herself which she posts on Myspace and has 100+ pics of her. Lastly, she always makes fun of my clothes, the music I listen to, and my race. I don't wear America Eagle and Macy's like pretty much everyone else does or listen to mainstream radio rap with pointless lyrics and I'm Korean and quarter Irish. I hate it when she tries to speak "Chinese" by making sounds like "Ching Chong Chang"I just don't want to be friends with ditzy, ignorant, person anymore. She's really getting on my nerves and I want to just try to drift away from her and get a new group of friends. And if you have any come backs, those are greatly appreciated! Haha =D