Don Miguel Ruiz's Four Agreements was based on his pillars for throwing off the negative influences of the external and instead living a life serving one's internally-created demands. I outlined these in my original summary of the book. Accompanying the foundation were additional smaller insights that I found useful.
Here are some of those thoughts:
1) The attention of others is the most desirable reward. Soon, we become copies of other people's belief systems because we see how similarity gets attention. In seeking the reward of attention, we become something other than ourselves.
2) Justice means paying once for a mistake. We often deny ourselves justice by paying over and over for one mistake through our thoughts, feelings, and attitudes.
3) The fear of not being accepted drives us away from our true selves and toward filling the roles or caricatures demanded by another's point of view.
4) Self-abuse sets the limit for how much we tolerate from someone else. Those who do not value themselves at all will tolerate endless abuse at the hands of another.