How to look pretty in the summer?

Well summer is here and there is a guy I'm really into and there's a swimming party coming up and I want to look pretty. I need help! Any videos, links or advice? I need help with makeup and outfits. Please? For the makeup, I'm looking for something light for teens But using eyeliner too! (Yeah I'm picky) And maybe help with hair too? Don't know the hairstyle but my hair is dark brown with carmel highlights (longer than my shoulder).