1. No WiFi, Bluetooth, or any other wireless crap...especially cell phones. All that can be easily intercepted/monitored with the right equipment. If you must use cellphone, get a 'burner'.
2. Use a wired-only router with NAT and SPI enabled hardware firewall. Have a pro set it up properly, if necessary.
3. Use a VPN not based in the jurisdiction of 14-Eyes Surveillance Alliance, or at the very least a High Anonymity Proxy.
4. Get a PC with DVD burner or player, and become skilled in using Linux LiveCDs like MX Linux, Linux Lite, or higher security distros (Kodachi Linux or TAILS).
5. Stay far away form Facebook, Twitter and Gmail. Limit your use of Google to Linux Live CDs.
6. Never ever trust anyone with access to your computer, passwords, etc. That was Mark Salling downfall.
7. Use both Bleachbit and CCleaner before you shut down the computer for the night. Make it habitual.
8. If you use Windows OS, cap it at Win 7...Win 8, 10, & 11 are stuffed to the gills with corporate malware,and every successive rendition will be worse. Start teaching yourself Linux before Win 7 becomes as useless as XP Pro. MX Linux or Linux Lite are the easiest for Windows expats to learn.
9. Buy a good (microcut) paper shredder for documents...or a fire pit works too.
10. Avoid all IoT devices....you sacrifice privacy for whatever small convenience it brings.
11. If you are in the USA, join the 'National Do Not call Registry'.
12. If an email provider wants your real name, phone, and all that...flip it off! Onmail, Protonmail and Mailo are better alternatives.