As a sophomore in college, you should have a game plan in place pretty quickly! Check with your school to see if they have a Pre-Law advisor. Law students come from all sorts of majors. You need to focus at this point on ability to pass the LSAT and be accepted into a school, as well as taking courses to help prepare you for the rigors of law school. I always recommend looking at the LSAT, perhaps find a study guide at the library, bookstore, or on-line. Particular emphasis on the section called the "logic games." There are LSAT prep courses available, but it's important that you get an understanding of this test and start preparing for it!
Coursework: Take whatever you can to challenge your thinking and writing skills. Additionally, I recommend a Logic class (usually in the Philosophy dept), public speaking, and debate.
As to what the schools are looking for, other than good grades and academic preparedness, I hope others will answer, as I'm not really sure. Leadership, volunteerism, etc are probably part of that mix. You will get plenty of opportunity for legal volunteer work in law school. Look for social service opportunities for now - working with families who have loved ones incarcerated, etc.
Thank you for your interest in law - best of luck!