Grad School 2: I want to go to grad school, so what should I do?

Suppose you've been mulling over graduate school, and you've decided that it's for you. You have a good reason - maybe you like research, or maybe you want to teach, or maybe your plan to save the world (or maybe just a secure career with some hope of advancement) involves having an MS or a PhD - and you are OK with the commitment. Now: how do you actually do it?