Since research is a major part of graduate school, discuss your research experiences as an undergraduate or at previous jobs. If you published articles on the education system in America for a few magazines, discuss your research for them and how this prepared you for the work you'll do as a graduate student.
If you haven't held any paid jobs, include any volunteer work you've done because this could still be related to graduate school. If you volunteered at a battered women's shelter while a sophomore and you're applying to a graduate social work program, talk about your experiences there and how this influenced your decision to enter a career in social work.
Mention some of your most significant accomplishments as an undergraduate. If you started your university's first academic journal with the help of some professors in the English department, state that since it was started two years ago, the number of subscriptions has gone from 200 to 500, and that more freelance contributors have sent quality articles.