First principles thinking is a cycle of breaking a situation down into its core pieces and then putting them all back together in a more effective way. Deconstruct then reconstruct.s1
Elon Musk explains first principles as: "What is the most efficient way to solve a problem if you started from scratch? If you look past humanity’s attempts to solve it, what is the best approach if you reasoned back up from its fundamental principles?"
To learn how to think for yourself, apply first principles thinking. It does not remove the need for continuous improvement, but it does alter the direction of improvement.
To identify which system is worth optimising, use the second mental model: Local or Global.