Beach 13th Birthday

Me and my friend ane having a beach party for our 13th birthday, and we need some ideas. We have about 5 v.i.p. Girls who we want to be dressed in something different than everyone else. Also the birthday girls need to be the most knowdisable people at the party. We are expecting about 60 kids at this party too! we just need some ideas of what to have, and accesories, or decerations! thanks!!