One day Ima write a whole piece on social engineering, but in the meantime here is my number one tip on how to not being a walking security hole:
LET PEOPLE BE WRONG.
No, you don't have to correct them.
The easiest way I have learned to get people to spill shit they shouldn't be telling you is to be wrong about something.
People love to be right. Let them correct you on a small thing, first, then they will feel good about telling you SHIT THEY ABSOLUTELY SHOULDN'T BE SAYING.
If I can resist correcting an oversized goon who's been harassing me for four years, as he blathers abject nonsense at me non-stop, you can get out of the habit of correcting people who didn't directly ask for your help.
Let them be wrong.
Let them be LOUD and wrong.
It's enough that you know.