Buy your own hardware components and build your own computers, use only open-source OS and software (any linux distro for general use, Tails if you're really locking yourself up in a basement), use encryption for everything, only access the Internet through encypted tunneled connections (a VPN or TOR), start using darkwebs more (like the TOR network or Freenet; the more normal people use it actively, the more it will become a viable alternative to the www for normal things also)... When using the www, avoid the large tracking companies (no Facebook or Google, obviously) and use blocker addons to stop trackers. Use different search engines.
Stay off the internet altogether if you want to be super safe. Don't buy equipment that has connections to the internet unless you really need it. Use smartphones with removable batteries (to be able to completely go off the grid if you want to).
...Or alternatively, don't do anything that makes you require any or all of the paranoid privacy measures mentioned above.