Assuming you mean law school in the United States, these steps should help:
1. Get good grades all four years in college. You do not need to major in pre-law; law schools accept people with many different types of bachelor's degrees.
2. Study for and take the LSAT. Take lots of practice tests first so you will be ready for the real thing. There are self-study books you can purchase, or you can even take an LSAT preparation course.
3. Involve yourself in clubs or sports in college.
4. Find ways to perform community service.
Definitely some good basic advice but, like Eliminator said, it might be more useful if you post it under the thread that actually posed the question you're answering.

Hopefully you'll come back on the board and let us know whom you were helping out!