When you understand how stupid computers are, mastering them and staying secure while using them are child's play. (That's why children are so good at it too)

Security can be broadly divided into keeping your files and stuff safe and staying safe on the internet.

Offline Safety

This is applicable to people who never connect to the internet.

If you are absolutely alone, with no access to outside world, nobody coming in to chat with you, no new pen drives going into your USB ports; the only person who can delete files on your computer or otherwise cause avoidable problems is - you yourself

Assuming you don't indulge in self-harm, you should learn to protect yourself from others who (inadvertently at times) do harm to your files. Following these broad steps can help you prevent such unforeseen mistakes.

Online Safety

The web is a place full of all kinds of people. And the moment you connect to the internet, you are leaving the safety of your walled house. Anyone, potentially anyone could harm you.

You can stay strong and safe with some basic precautions.

I plan to expand this section later.

Private, secure communication

Encryption is one word for safe communication on the net. Read about public key cryptography which is now widely used to ensure that your communications are readable only by you and the recipient.