Dont smoke, dont go silly on drink because what the fuk is fun about being drunk other than being a tit to others and vulnerable to yourself. Know now what you want to become, and start it. and above all else, WEAR yourself to death. wear everything until it becomes a fuked up rag cloth. Use this age to your advantage as your late teens and early 20s you are in your prime. Be 18 and ride the fuking rollercoaster year ahead of you, dude, because no-one has a perfect year.