The benefits of having a mentor for graduate school is worth an undergrad's effort to find one. A mentor guides you as you seek graduate-level education. That person — usually a professional already established in a specific field — is someone who takes a special interest in you and helps you make connections; writes letters of recommendations; arranges interviews and internships; gives advice on which classes to take or where to go to graduate school; and offers an inside look at your chosen career.
You can seek out mentors through information interviews and internships, and by participating in field-specific activities. Try networking to connect with a mentor: Let faculty members know that you're looking or try the alumni office. Keep in mind that many alumni have signed up to be mentors but are never called; this is an underused resource for finding a mentor.
Finally, you may simply identify someone whom you want to model your career on and just ask that person to be your mentor.