Sacrifice yourself for the well-being of others. Find contentment in a life by dedicating yourself to the service of others. Work hard and be as good as you possibly can be at what you do, so that you possess the requisite skills to make a meaningful and substantially positive impact on the lives of others.
Be honest. In all of life, honesty and transparency are of the utmost importance not only in dealing with others but also with oneself. Without complete honesty, there is no reason to completely trust anyone, including oneself. Transparency removes the need to simply hope one is trustworthy.
Follow the guidance of this quote attributed to Einstein: "Everything should be made as simple as possible - not simpler."
Use scientific reasoning to continually improve. Progress in any field of endeavor can be accelerated through the process of science. This statement is particularly applicable to the field of investment decision-making which is truly in its infancy in that respect.
On a micro basis, endeavor to play the odds in every situation regardless of the immediate outcome, knowing with confidence that you will ultimately be victorious. On a macro basis, attempt to maximize the trade-off between positive and negative sources of return.

Positive sources of return for any investment are:

The income, which is relatively predictable
The change in price (i.e., capital appreciation), which is what you pay an investment manager to predict

Negative sources of return for an investment are:

CIA Principles