first day do:
meet new people
smile
find your friends (assuming you went to middle school w/ these people)
make sure you know your way around.
wear your favorite clothes (NOT A SUIT YOU friend)
first day don't:
let your spaghetti show
pack your backpack so much it looks like a turtle.
carry around a stuffton on stuff in your hands, highschool students can always tell the freshman right away because of this.
sit alone, eat alone.
try to be someone you're not
highschool is a breeze. it really is. just let it come naturally and don't waste your youth as a depressed or jank mass.