Don't feel bad about it, for starters. They are probably too self-concious to be a true friend - and those are the ones that count, right? Don't be afraid to hang out with others that are ignored, they might be a great friend that your really missing out on.
Be yourself in front of people, a few might see the real great girl that you are, and want to hang out. Before you know it, you may have a few friends that stand out with you, are different than the others that are too afraid too stand out. True friends are a choice treasure; I have a few true ones that I can truly trust; and that I know won't dump on me if I'm different than the others.