Don't post pictures of your naked baby
Do not publish pictures that could easily end up on some kinky discuss forum like nyx.
Realize, that public profile is public with all you publish on it.
After posting, you are no longer owner of author rights to your own pictures. Which means the platform becomes the owner with all the copyrights.
You gotta follow their rules or you get block.
There's a record of all your clicks. That leads to targeting ads that are relevant for you, which always doesn't have to be cosmetics.
Do not publish pictures of your friends without their consent.
Do not publish photos / videos to which you don't have author rights at first place.
Secure your account with two step verification
Check out your settings and apps you've connected so you can define, which data the platform can collect about you
Do not tage a place where you live
Don't click on weird links even though they come from your friends
Don't open apps like: "What did you do in your previous life" or "Where you'll be in 5 years"
Do not post anything you might regret
Don't make your kids look like morrons - they can sue you later on (like in case of this Austrian family)
Don't go in to unnecessary fights when you don't have the arguments
And mainly, don't make everything in your life spin around your social media