Contact professors with whom you'd like to work. Show that you have knowledge of their work, and express your own interest along those lines.
Contact the graduate diversity coordinator. Introduce yourself by giving a personal and academic account of who you are and why you'd like to pursue graduate school.
Arts & Humanities: Alberto Ledesma
Biological Sciences: Audrey Knowlton
Mathematical & Physical Sciences: Ira Young
Social Sciences: Ira Young
Go to your letter-writers and provide a well-organized packet of information. Provide a deadline at least a week in advance of the due date. As a courtesy, give them at least a month to write. In the information packet, provide a short statement on how you've prepared yourself for graduate school as well as what you plan to pursue in graduate school. Be specific.
Squeeze out blocks of uninterrupted time when you can devote yourself to the application process.
Never leave things for the last minute.