Qualifications
Just surviving college doesn't qualify you to be a college counselor. In fact, there are lots of hoops you're going to have to jump through if you want a career in this field.
First off, you're going to need a bachelor's degree, preferably in something like counseling, psychology, communications, or social work. Even if you elect to pursue a major that's completely at odds with a job as a college counselor—say, in electrical engineering—make sure you find a way to fit some counseling coursework into your class schedule.
Once you've completed college, it's time to move on to graduate school, where you'll earn a master's degree in a specialized field like counseling, higher education, or human services. Again, whatever graduate degree you earn, go heavy on the counseling coursework. You especially want to take classes on career counseling, as well as classes on counseling techniques and different ways to handle student academic, social, and behavioral issues.
By this time, you probably have a good idea of where you want to practice the fine art of college counseling, which means you need to figure out what the licensure or certification requirements are for the state where you plan to teach. That's right—most states require that you get yet another piece of paper to hang on your wall.
Moreover, be aware that the licensure or certification process may require you to complete an internship or mentoring program with an experienced college counselor, where you'll learn the tricks of the trade through firsthand observation of a master.
So, you have your bachelor's degree. You have your master's degree. You're a certified college counselor with a mentoring program under your belt. At long last, you're eligible to go out and get yourself a job at a high school. However, keep in mind that part of your career as a college counselor will include you taking continuing education coursework until, oh, the end of time.