Buy a good travel guide written for budget travel. My two favorites are
Let's Go and
Lonely Planet because they include an amazing amount of info that you need on the road and while you're planning your adventure.
Read through those sites and buy the books. Educate yourself in advance.
Pool as much
cash as you can and have access to it even if you don't want to spend it. Just like in normal life, being flat broke is rarely fun and it can quickly suck you down on the road. Get a temp job that pays decent and work to save, save, save!
From the Let's Go site...
There's an old saying that goes: the difference between travel and tourism is that travelers go places to learn new things and tourists travel to confirm what they already know.
What can I say? Free your mind. If you want to enjoy something, you probaly will. If you think it's overrated before you get there, it certainly will be.