- Don't put anything about your real self on the internet.
- What goes in the internet will stay in the internet forever. Mind the info you get out there, even if it's supposed to be a private message. Leaks happen.
- Do not use real name and address, to be pseudonymous at the least (or better, completely anonymous). When setting up accounts, make sure that they don't link to your identity (specially email which is the center of your online identity nowadays).
- Not everyone on the internet is who they say they are. On the internet nobody knows you're a dog.
- Be clear on what grooming and pedos are and that they're out there to catch you off-guard.
- Learn about spam, scams, malicious sites, phishing, etc. look like and how to prevent damage.
- No matter what happens or how deep in shit they are they can come to you for help. You won't approve the ugly things they do, but you will forgive them and help them clean up the mess. If in doubt, come get help. The earlier you ask for help, the faster the cleanup.
- Make all of this real by showing them what could happen. Show them real cases.
- Once your kids are old enough to understand this then they can go on the internet 100% unsupervised.
- Never answer security questions with the correct facts. Make up a pattern of answers that you can answer, treat them like passwords (Use a Password Manager).