How can i get rid of her?

ive got this.. well friend, shes realyy realy annoying and i cant stand her.. and she is soooo childish and shes always following me around andd omgg staring at me :@ and shee smells realy bad and has realy bad breath , its disgusting. and she is always trying to split me and my friends boyfirends up :O how can i tell her nicely that i dont realy want to be her friend?