How can i improve myself for high school?

I'm starting high school in August and I'd like to improve myself before then. Any ideas? I'm 5'4, 120 lbs (I'd like to lose a little wheight), blonde wavy hair that i either straighten or curl, green eyes, for make up I usually just wear eye-liner and mascara, and I guess you could consider me a girly girl even though I'm super nerdy. Lol. Please help me out on this. (: