Disable some or all of Amazon’s pre-installed apps (I suggest using the manual option and just checking the apps you know you don’t want or need).Change your screen density options (to make text and graphics look larger or smaller).Update: Recent builds of Fire OS won’t allow you to fully replace he default launcher, but you can hijack the home button so that pressing it will open a third-party launcher app.
Change the default launcher app (you can use something like Nova launcher to make Fire OS look more like stock Android).
How to use an SD card with Amazon’s Fire tablets.How to sideload apps on Amazon Fire tablets.
How to disable Amazon apps and features.Hack your Amazon Fire tablet with Fire Toolbox.How to install Google Play on the Amazon Fire HD 10 (9th-gen).How to install Google Play on the Amazon Fire HD 8 (2020).