I'm not on the whole #DeleteFacebook band wagon. (More Info: The Problem With #DeleteFacebook - Slate.com.)
If you feel you really need to, go ahead. See you on Mastodon. (https://chitter.xyz/@programwitch)
I however need to use Facebook for several reasons. So not leaving. That doesn't mean I'm now a fan. I'm not. It's just one of many needed tools.
Settings > Security and Login
Go through and double check all of your security and privacy settings. You should be doing this from time to time anyway.
Settings > Privacy
Check on who has access to what. Select: only me (meaning you), friends, friends of friends, or public.
Settings > Apps > Apps, Websites and Plugins
From here you can turn the whole Facebook Platform OFF If you do, you will not be able to use Facebook as a login on other sites, services, and some games.
Settings > Apps > Apps Others Use
Uncheck everything you don't want to share. I only have my website checked.
Settings > Apps
Go through the list of apps and remove any you no longer want to have access to anything. My list had quite a few games and old websites listed. Cleaned out my list to just the trusted sites for login, etc.
If you have any more settings or use suggestions, please feel free to leave a comment.