There are many different types of lawyers. But, to begin covering the basics, I encourage you to work on developing your writing skills, to include truly learning grammar. I have seen many cases about the interpretation of a law, where the discussion revolves around the parts of speech and the sentence structure, and I am totally lost! You also want to work on analytical thinking skills. Colleges offer a course called "logic." You should take it. Also work on public speaking and debate. Even if you never take a case to trial, you will still have moments where you are trying to settle a case with opposing counsel or negotiate a settlement.
I encourage you to dabble in all subjects while in high school, so you at least have a basic familiarity with them. Law draws from all fields. For example, a traffic accident might hinge on braking distance for a vehicle. You have to look at the type of road surface, weather, visibility, friction, condition of the car, and condition of the driver - lots of science! Or perhaps you need to look at a company's financial records - you would want some background in principles of accounting. While big law firms would hire consultants for some of this, there are many smaller firms who cannot afford to hire consultants. At the very least, you would want to know whether or not there was possibly something amiss - so you only hire a consultant if there is really a need for one!
Your college grades will be important. What subjects you take will be less important, as lawyers come from all backgrounds. I encourage you to see if the college has a pre-law program, and join it. Possibly get involved in student government. Try to take some law classes - criminal law, business law, constitutional law are all usually offered in college. Try to find ones that have demanding professors, so you get a better feel of what awaits you in law school.
Also, look at the LSAT. That is the test for law school admissions. It is hard. Look at the logic games. If you are serious about law school, you will need to learn to master the logic questions. There are programs that prepare you for that test - classes you can take, probably outside of college, for a fee.
Best of luck to you!