The reason she can get away with wearing these outfits is because she is so confident when she wears them.
In order to be confident, there are a few things you must do. First, you must figure out what your style is. Not everyone has one distinct style. There are no rules saying "You must only wear preppy clothes" or "You must only emulate the Bohemian style." Choose things that you feel comfortable wearing, and wear them with confidence. You also need to stop worrying so much about what people think about you. Almost every weekend, my Dad says something about my outfits being weird, which is not exactly a self-esteem booster, but I learned to just blow it off. If I feel comfortable in my clothes, then I don't care what anyone else thinks. Anyone can pull off anything if they love it and feel confident!
Take a fashion risk and wear something you feel great in, even if it isn't the most trendy or expensive thing. Your confidence will shine through and people will notice :]