I would suggest starting with people you're familiar with in real-life, such as family or friends. You don't have to fill in all the information if you don't want to, but the basics such as where you're from, your gender, etc, are good. You can adjust privacy settings for a lot of the information, too, so that people who aren't added as a contact can't see it.
accountinglad wrote:
As a general rule don't post stuff that you wouldn't want your parents or employers to see
This is a good rule that many don't follow.