Yey... more newbs to absorb into Fandom. Soon we'll take over the world, one person at a time.
Things to do at your first convention:
1 - show up in costume
You'll look spiffy and lots of people will come talk to you.
2 - Volunteer! (my first convention I volunteered and it was a blast--I got to see a lot of what goes on behind the scenes of a convention, and even had the opportunity to spend more time with the guests than most ordinary con-goers. Also, it's a perfect way to meet lots of cool people. Guess where I met my husband? Yup, he was on the convention committee at my first convention...)
3 - talk to random people (yeah, this takes a bit of guts, but guess what? Everyone is friendly and you'll always be able to find something to talk about since we all have at least one thing in common - an interest in anime)
4 - Attend as many panels and main events as you can. If you see a panel on something and you have no clue what it is, then go to it anyway... you may learn something.
5 - Visit the vendor's area at least once... I'm sure you'll go back there many times with additional money to pick up items that you absolutely MUST have.