Okies, here is a list I came up with after thinking about it and talking to other congoers.

Do's
-Cosplay if possible
-Bring an emergency sewing kit if cosplaying
-Have your ID with you at all times
-Watch out for other peoples props and avoid damaging them
-Bring friends
-Keep hydrated and bring snacks
-SHOWER!
-Seriously consider getting a hotel room
-Bring something to put your stuff in
-Have fun

Don'ts
-Glomp without asking first
-Piss off staff
-stalk people
-Be hyper-active
-Go anywhere with strangers, especially not if you're a minor
-Argue with convention staff
-Touch other people's costumes without asking
-Smack people with yaoi paddles (Without asking )
-Throw things at people
-Let others you don't know watch your stuff for you
-Talk down to other cosplayers
-Buy overpriced items just because you think you'll never find it again

Whew, thats alot ^^;  And these arent even detailed. But im sure you wont need any more that this. If you do just ask me ^___^