Define Your Axioms and Principles
These are the foundational truths that are taken to be self-evidently true that are used to build arguments, solve problems, and navigate the world.
In some cases, the axioms and principles are held to be universally true, such as in mathematics. In many other cases, there is some sort of logical leap that is made to decide what the axioms and principles are. Although they should ideally be self evident, a person's temperament and life experience may influence how big of a logical leap they make.
Once axioms and principles are defined, you need to be consistent in applying them - there should be no contradictions in how they are applied. They set the standard that everything goes by so that edge cases can be handled consistently without bias or ulterior motives influencing the outcome.
Principles become especially important when dealing with uncomfortable and challenging edge cases. Clear cut cases are not why axioms and principles are important. If you start coming up with ad hoc rules to justify special cases as they come up, then they are not really axioms or principles. They become radical ideology.
Axioms and principles can emerge through iteration and evolution, where over time the ones that survive are the ones that are most likely to be true. They are general enough to guide in a useful way, but not so general that they become meaningless. A balance between freedom and constraint is necessary.
Principles and axioms can change or be updated in some cases, especially in cases where they lead to minor contradictions or if they are no longer useful. If they never change, then they are either old and conservative truths with further underlying axioms and principles, or they may be radical ideology. If they don't change in cases where it's clear the principle or axiom was wrong, then it becomes radical ideology. If principles and axioms are constantly changing with edge cases, then they might not actually be true. They need to be general enough to be true but specific enough to be useful.
Some common principles:
Failure teaches you more than success