Go to the “Privacy Settings” link and click on “Profile”. In this section you can change your security settings for your “Basic” and “Contact Information” sections. Under the “Basic” section tab, you will see a list of items in your profile that you can adjust. These include your profile, basic information, photos/videos, friends, and work/education information. Look at each one of these and determine how secure you want each one of these sections. If you are unsure, change all of these settings to “Only Friends” with the appropriate drop down menus and click the “Save Changes” button.
Other Facebook security settings are under the “Privacy Settings” section. From here you can adjust are the “Search”, “Application” and “News Feed/Wall”. Each of these sections has several checkbox options you can choose for what your friends can see on your Facebook page. However, you should consider adjusting the “Search Visibility” option to the “Only Friends” setting.