If your game is built on a good basis and has promising KPIs, you can start optimizing through variations, e.g. theme, colors, camera, levels & obstacles.
Use a software like “git” to always track your changes and for the possibility to go back to an earlier version.
When your game fails, analyze your best & worst performing videos together with the whole team!
Look into gameplay readability, camera and themes and if they accomplish your goals the best way possible.
Afterwards define clear actions & share your learnings with the team.