100% dox-proof guide
1. Don't post any personal info online. This includes things like: the state you live in, the exact temperature/weather where you live, any kind of photos even if exif data is scrubbed, details about your past that could be identifiable like "in 6th grade everyone called me the energizer because I shoved a AA battery in my foreskin".
2. Always use a VPN (preferably a free one so there's no money trail) or Tor at all times. If a site blocks all the good free VPNs and Tor (4chan for example) that means it's run by feds or fed collaborators so why would you even want to post there. If you really want to you can find proxies that aren't b& yet to chain with your VPN to post on sites like that.
3. Be as anonymous as possible. Be aware that filename patterns, your interests/fetishes, all sorts of posting habits including how you grammatically structure your sentences, etc. can help greatly to identify you.
4. Never phonepost. Only fags use iOS or android.
5. You can post believable details about yourself that aren't true to throw off any present or especially future doxing attempts but be aware that this is lying so God and Jesus may send you to hell for breaking one of their ten commandments.