Go to the ExCo Fair, held at the beginning of each semester. You can sign up for the classes you want to take, as well as ask the instructors any questions you have about a class. Most classes select their students by random lottery, although some have an application. If you're accepted into an ExCo, you can register on PRESTO (just like your other classes). (If you're not an Oberlin College student, you don't need to register at all.)
