Are you looking for a way to earn some extra money? Did you do well in school, or on standardized tests? Offering tutoring services may be a good bet for you.
I've been a private tutor for the better part of seven years now. It kept me in spending money as a part-time job in college, and it has turned into a full-time gig for me over the last few years. The best part about it, though, is that it's an easy concern to keep going whether you have three or thirty hours a week to devote to it.
What to Tutor
I've taught everything from high school writing to college calculus to professional certification exams for public school teachers. That's just the tip of the iceberg: there's a market for tutors for every standardized test in existence, and probably every academic subject at every level, too. Heck, much of this article probably applies to things like music lessons, as well.