The top law schools are competitive. For example, Harvard only let in 16.5% of people who applied. http://hls.harvard.edu/dept/jdadmissions/apply-to-harvard-law-school/hls-profile-and-facts/
Agree with all the above. GPA is important, and LSAT scores. Writing is also important, for you will be writing an essay with your law school admissions. Writing skills will help with success in law school.
Besides grades, there are other things you can do in college to prepare for trying to get into law school. If your college has a mock trial team, you can join that. You'll develop lawyering skills and that would look good on a law school application.
Also, you may want to consider law classes offered by your college to determine if you want to be a lawyer before committing to applying to law school. You can also look at interning at a law firm. That way you can meet lawyers and see what they do and if the legal field is a good fit. I decided I wanted to be a lawyer after taking business law at my college.