For each Facebook contact item that you have in your profile you should set custom privacy settings (as pictured below) so that contacts that you aren’t close to don’t have access to your phone number and/or email. It’s a small change but it can save you the hassle of being pestered by people you don’t know well. Also, protecting your privacy is generally a good practice to get in the habit of doing.
As a side note, this is a great area to take advantage of friend lists. By getting in the habit of grouping your friends, you can ensure that you are navigating Facebook safely through privacy settings that are attached to your friend lists.