How do I be more girly?

Mkay so when I'm around people I tend to disregard everything I know and just go on impulse. Meaning I do not act girly at ALL! I'm 17 and even though I'm not considered a tomboy, I'm not a girly girl either. I don't want to be all conceited, just how do I be more cly and girly? hah, hope this made sense.