Um . . . I kind of need more background information but I'll try my best. Are you and your crush friends? Do you have reason to think he might like you back? What are you doing for the fourth? (party, bbq, fireworks, swimming etc.) I guess just act like yourself but definitely talk to him. If you're too shy to get him alone, talk to him in group conversations. Smile at him, playfuly grab his arm, laugh at funny things he says (but not like a dying hyena laugh that stretches on forever. It's not sexy) As for what to wear, I suggest cute shorts or capris with a colorful, flirty tank top. If it's not too cliche for you, you could layer white & red tank tops with denim shorts, but i don't know if you want that. Wear your hair down, maybe scrunch it for the natural waves look. My boyfriend loves it when I do that. Don't be nervous and have a great time! If you give me more details I could probably help you better