kebab_definite use Chrome in Incognito mode.
All joking a side, it's virtually impossible. Unless you only use FOSS apps, and never browse the web.
You will drive yourself mad trying to achieve the impossible. I'm guessing your not Snowden, so just reduce your digital footprint as much as possible (less is more), consider a VPN, use reputable FOSS apps where you can, use an alternative to Google/ Bing search and don't log into Google/ Facebook etc accounts on the browser you use for everyday browsing. The browser you use everyday set to clear data on exit. Don't run crazy unique browser settings and plug ins.