Remember that you are now 18, a citizen who can be held personally liable for his actions, arrested, go to trail as an adult and are responsible for your actions. Those responsibilities do not begin when you are 18 and 1 day. They begin when you are 18. Keep the partying to a minimum. If you want, register to vote, but that can usually wait until the next day. Open an IRA--not exciting, but good planning. Thank your parents for all they did for you and think where you want to be when you turn 21 and how you are going to get there.