A principal's mindset means acting like the principal, which means taking ownership. It involves approaching every task as if you are the sole proprietor of that endeavor. So, whatever it is that one is doing- just act like one is the owner of that act. It's a profound exercise in understanding one's ego and the subtle nuances of emotional validation.
If you don't rest until something is done and it's done well- and you find the corner cases and you solve them without being asked, eventually you will notice its impact on the long-term. This mindset will allow you to have long-term people to play long-term games and would empower you to keep reinvesting in those relationships without spending a lot of time in transactional costs. You don't have to worry about trust because you know these people. When you make a mistake, an empowering trust relationship will tell you what you said a while ago and remind you how right you were. These relationships are the established resource of gratitude as we need to be reminded more than we need to be taught.
And eventually, you don't have to worry about what to do next or where to do it because it just merges from the previous thing. Opportunity unlocks future opportunity. It's even tax efficient. For instance, one can leave investments in place and they can keep compounding without having to take them out and pay taxes and then reinvest. These are just mild examples, but if we see through this mindset clearly, the network density of whatever act it is- keeps building up.
However, if one only follows the principal mindset and doesn't check on the ego- then one would not last long enough. So one literally has to embody the mindset for its own sake because of who one is, and that's how one acts, and that's how one gets things done, not because that is the resource of external reward and recognition.
The only person who will give you credit for the work you do or the actions you take- that no-one sees is reality. It's the only thing that will accurately reflect the work you did or the actions you took in life. People might not fully grasp your journey or efforts, but the impact you make in the world is the truest reflection of your work.
One major truth, therefore, of a principal mindset is: those people are not seen as experts, as an expert doesn't have an interest in what is true- instead the interest of an expert is in spouting his indoctrinated knowledge. That is where its truly seen that the people who form relationships with the dynamics of proving themselves as expert will have no interest in what actually works, they only have interest to get things done or how to do them.
