I tend to write a 2 page CV; I've always been told that more than this often doesn't get read. Don't include things such as your age, gender or race as these should not be required. Put your basic contact details (name, email, etc) at the top.
Next add some summary information about your abilities. This can take the form of a paragraph long personal statement, perhaps just one sentence, or some bullet points detailing your skills.
Then group the remaining information into sections: employment history, education, training, and perhaps a short personal one about your hobbies (one sentence). Opinion differs on the preferred order of these sections but personally I'd put the employment first.
In the employment history, put your most recent job first and write the most about the most recent stuff. As you go back in time, as a general rule, write less. There are of course exceptions to this rule - if your current job is 3 months in a grocery store but the previous was 10 years as a software developer you'd obviously want to write more about the developer job.