I would research (internet) whatever career you are interested in while you are still in college or high school. Speak to people in that field, read industry publications, attempt to get an internship and list the pros and cons of what you like about the career field you are considering. Then list your interests and cross reference these to the career you are considering. You should try to pick a career that is interesting and is something you like to do. That will help you actually stay interested and hopefully like your job.