Long gone are the days when 'career' counseling was only meant for students at college or university level, in an increasingly competitive world it is important and integral for a student's success later in life that they start planning for their career well in advance. For students in their early teens the most crucial deciding factor that outlines the path for a career later in life comes from the selection of subjects chosen usually in 8th or 9th grade. Therefore, a "Subject Combination" is not a new concept.
In most schools, students get to choose from 3 basic subject combinations, Pre-Medical, Pre-Engineering and Commerce. The names speak for themselves in this scenario, if you aspire to become a Doctor then definitely "Pre-Medical" is for you, and If you see yourself as an Engineer or an Accountant then Pre-Engineering and Commerce respectively, are the way to go, however, this is a very simplistic assumption and there is more to it which should be discussed.
As an early teen you may not be the pilot of your own life and your parents, teachers and inspirations may guide you towards a path. When you reach a point in your school life when you're finally ready to go to college / university, you'll realize that a wide range of specializations and careers await you and by the time you would be mature enough to take your own decisions . Getting the first step right is necessary. Suggesting from experience, for many students who are not yet sure what they would want to pursue in the future, Mathematics or Additional Mathematics as a part of your subject combination is highly recommended. It would help you get into various Engineering and Business fields and may even help you if you wish to go for a Social Science major, such as Economics.
You might also want to play to your strengths; this approach works best when you know what your forte is, if you're good at languages how about studying Literature? Believe me, it will definitely help broaden your horizons and a good grade would make a good impression on your college application.
Years spent in high school, are a fun, thrilling and memorable experience. Taking the right decisions and focusing on your grades and extra-curricular activities ensure that you have a solid foundation when applying to universities and colleges. There are thousands of candidates applying in universities at the same time and it's what sets you apart from them that would get you a place in your desired academic institution, once you're in high school it's never too early to start planning for your career.
Best of luck!