ANDY'S ANSWER: Career tests are meant to highlight careers that use your natural strengths and match your personality type as well as your interests. It's important to understand the basics of your personality like whether or not you are more comfortable working alone or with others, if you do better in a structured or unstructured environment, if you are strong in math, language, creativity or artistic skills, etc. It's also important to know what expectations you have for your career in order to be satisfying. Do you need lots of travel, high earning potential, flexability in working hours, something that lets you be outdoors, or have interaction with a lot of different people? Know what things you know you DON'T want to is just as important as figuring out what things you do like to do.
Look at 7-10 occupations that you think might interest you. Are there some that are similar? That will probably help narrow down the category of where you want to go.
Do some research as to what kinds of different jobs each career could have. For instance, if the medical field interests you, but you don't necessarily want to be a doctor or a nurse, there are hundreds of other careers that you could choose like in research, technical or teaching. You might want to major in something that will give you the most options and narrow things down as you go along.
Do some research on different jobs that sound interesting. Talk to the people who are actually in those careers. Find out what they love most about their jobs, and what they dislike. Ask them what things they had expected from their career choices that they had been disappointed with and what unexpected rewards they've found. Ask them if they were choosing now if they would do it all again, or go a different route.
Consider how much schooling you are prepared to take to prepare for your career choice. Also consider how that career may affect your personal life. Will you be able to go home at the end of the day and leave the job behind, or will you always be on call? Check out what the earning potential will be in the careers that interest you. Will the money you make meet your lifestyle needs? The other thing to consider is what is the availability of jobs where you want to live? Would you be willing to relocate if there is not a lot of job potential in your chosen field?
Sometimes the best thing you can start with is a "Things I would like" and "Things I wouldn't want" in a career list. After that, you can compare different jobs to that list and take a closer look at the careers that fill those requirements. You might be surprised at what ends up at the top of your list.