Make it short.
A good résumé is one that is read quickly. It is not necessary to keep it within one page, but you should keep in mind that the members of the selection committee may never look at the second page of your resume if there is one.
Make it clear.
Put the most important information on top of each section. Leave no room for guesses: members of the selection committee should not have to think in order to get your credentials right. Keep the format simple and straightforward. Too much formatting makes things more difficult to read.
Make it clean.
Check the grammar, spelling and punctuation of your statements and essays extremely carefully.
Get it checked.
Your Prelaw advisor can help you with your resume.