The most basic is really determining the difference between private key and public address. Many newbies, including me before, always fallen to the trap of scammers asking for their private key.
The difference is pretty explicit if you ask me. The problem is that newbies don't know what private keys actually do. If they knew going in that their private key is
essentially their wallet itself, a prospective scammer would have to lie pretty creatively to have them share it. OP was right to list that first, and what sharing it could mean.