Just the basics: For desktop: Mullvad browser default settings no customization, always on vpn (mullvad), alias emails (Simplelogin is great and somewhat user friendly).

For Mobile depends on device but lets say not a google pixel but an android: seperate necessary intrusive apps via a work profile using shelter), use pwas as much as possible via a privacy friendly browser (I like mull + ublock extension), an always on vpn (tip: mullvad has the option to block trackers also), again alias emails, disable as much bloatware via adb, and lastly switch to foss alternatives for apps where you can.

Besides that dont fall into your normal patterns/interests switch it up between each identity. Hope that helps