1. have a browser that doesn't store cookies, use that for casual browsing.
2. use an adblocker at all times. user agent faker too.
3. use pgp email with no subject lines with offline mail clients.
4. avoid social networks, centralised services. set up your own for other people you know.
5. keep informed. keep looking for how to give away less information. keep looking for which new information is retained. e.g. karma police revelation.
2. Depending on your settings, an agent faker can make you move identifiable should it project a unique or impossible agent. Even one set on to a randomized list can be telling as so few people use such settings. You have to be careful.
3. And who is going to read these emails without subject lines?
4. Unless you are going to live in a unibomber-style shack, you need some form of public network. And any successful private network eventually expands to the point of being public. Even facebook was once private.
5. To keep informed you'll need to read and communicate online ... which only makes 1-4 more difficult.
2 - I agree with you on the user agent. Don't fake it unless you are going to make it more common. Perhaps turning Linux into Windows is a good idea (but make sure you do it right).
3 - I would say many if you recognise the sender.
4 - That's going a bit far. People can live without facebook but they usually fall back to email or other poorly protected methods.
5 - Agreed.
Forgot to mention disabling referer where possible, which you can test with https://www.whatismyreferer.com