2) Start adopting new pseudonyms. Use a different one on every site, and a password keeper to help you stay logged in. If you happen to forget, don't worry. Treat every account as disposable. These are not "you". This is not "your brand". These are merely tools that allow to into a walled garden party wearing the mask of anonymity.
3) Do not mix your two online personas. Keep your politics, jokes, and personality in your pseudononymous accounts. Keep your boring safe opinions and pictures of dogs in your primary account. Don't talk about anything in your real life in your pseudonymous accounts, even the weather. Reserve that kind of discussion for in-person friends only. If you make a mistake, just delete the account and make a new one.