Tips for First day of highschool? :(?

I'm starting highschool this year, and i'm superrrr nervous.. I have a group of friends that I always talk to. And it's a big school, so i doubt i'll see them much. So it's obvious that I need to meet some new people. Any tips on how to be more outgoing? I'm really shy at first. :/ Also, outfit or hair ideas for first day? Thanks guys. :)