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If you're logged into Facebook, doing so will take you to the News Feed. If you aren't logged into Facebook, enter your email address (or phone number) and password in the top right corner of the page and then click Log In. It's in the top right corner of the Facebook window. This option is toward the bottom of the drop-down menu. It's on the left side of the Facebook window. . Edit is on the right side of the window. You'll find the "Who can send you friend requests?" section about halfway down the Privacy page. It should be below the "Who can send you friend requests?" heading. Doing so will reduce the people who can request you as a friend (and, therefore, see you in the "Suggested Friends" menu) to people who are friends of your current Facebook friends. It's in the top right corner of the "Who can contact me?" section. This is the "Do you want search engines outside of Facebook to link to your profile?" option. Doing so will ensure that people won't be able to look you up in Google, Bing, or any other search service outside of Facebook's search.

Summary:
Open the Facebook website. Click ▼. Click Settings. Click Privacy. Click Edit next to the "Who can send you friend requests?" option Click the Everyone box. Click Friends of Friends. Click Close. Click Edit to the right of the last option on this page. Uncheck the box next to "Allow search engines outside of Facebook to link to your profile".