Choosing a career direction that takes into account the sort of things you are interested in makes good sense. This ensures that you will be motivated as you have a natural inclination already in a particular area.
In addition to the online interest tests mentioned below, you can take the Careers Portal Interest-Profiler (CPIP) to measure the relative strengths of your interests.
This instrument also provides you with a free printable report containing a summary of your career interests, along with some occupations that match your interest profile.
You will need to login to take this test as your results will be kept for you in your Career File.