Read the text of the wait list letter carefully. Admissions offices at some law schools have different requirements to accept a spot on their wait lists, from responding to an email to sending in a postcard confirming your spot on the list. These often have specific deadlines, so make sure to respond quickly.
Revisit the law school's website and research what sets the law school apart from its peers. Use your results in the next step.
Write a letter to the admissions committee indicating your continued interest in the law school, and explain why you would be a good match for their program. Be sure to mention any new accomplishments, achievements or awards you have received since submitting your application. If the law school is truly your first choice and you would definitely attend if accepted off the wait list, be sure to say so in your letter.
Ask a professor or a supervisor for a supplemental letter of recommendation. If possible, tailor this letter to the specific law school to which you are trying to gain admission.
If you are still in college, send in an updated transcript if it raises your undergraduate GPA.
Visit the law school campus, if possible, and sit in on a class. This is an excellent way to show the admissions committee that your interest in the law school is sincere, and would help make your letters of continued interest more compelling.
Fill out all necessary financial aid documents. Most schools require the Free Application for Federal Student Aid (FAFSA) to make scholarship and loan award decisions, so be sure to submit these to all schools you are considering.
Consider retaking the LSAT. It is offered in June, and if you raise your score, you will become a more attractive candidate.
Don't forget about your safety schools. Many law schools do not start admitting students off of the wait list until after the first seat deposits are due in mid-April. You will probably have to put down a deposit at another school before hearing back from the school that wait-listed you.