A curriculum vitae is a résumé-ish document that one gives to employers to inform them about your qualifications for a position. On this side of the ocean, they're mostly required only for academic positions. Employers outside of academics tend to call the thing a resume (the presence of accents depends on the employer's pretensions) to emphasize that they're more interested in your work experience and practical skills. I'm going to assume that if you're reading this, you're looking for an academic position.

At the top of a CV, it's expected that you give the employer various ways of contacting you. At minimum, I'd recommend an e-mail address and a snail address; you might want to include a landline and/or cell phone number as well. If you're currently still going to school at another institution, you should give both a current and (semi-)permanent address.

For each section in the CV, you have a choice of how to order the various things that have happened to you in the course of your life. First, you can order them reverse chronologically, so that the most recent events in a category come before later events. Second, you can order them by relative importance, but this second option can be a bit confusing to read. The last thing you want to do is give your potential employer a reason to be confused by your CV.

The first section of a CV should list the various degrees and institutions of higher education that you have attended. I've seen people somewhat obsessively quote grade averages for each degree, but I think only the last degree's GPA is really relevant. If you haven't graduated yet, give the expected month and year of graduation. Be sure to list the location of the various institutions, as well.

After chronicling your education, it's helpful to list your main academic interests. Devote less than a paragraph to this. After that, you can add any number of categories of things that you think your employer might be interested in. Things like: major research projects you've done, published papers you've written, conference presentations you've given, all the way down to the various professional memberships you hold and the languages you speak.

If your academic life is quite long, you might want to consider picking and choosing what you want to report. Two to four pages is a good length for a CV. You absolutely shouldn't lie or withhold the truth in a CV, but if some of the things you've done aren't really relevant to the position you're going for, it's permissible to leave them off.

Because of this, some people advise writing a new CV for each position you apply to. I think that's a bit excessive, but there's something to be said for taking care to tailor your CV towards the kind of employer that you would find desirable. After you've completed your CV, you should definitely have a critical friend of yours give it the once-over, to make sure there aren't any embarrassing typoes or anything like that.