Do you conduct post-mortems on your projects? How about on your decisions?
Each time you make a decision of any magnitude, write down the outcome you expect. Eventually the outcome will grow to a list that you can revisit. Just as post-mortems make future project better, so this simple process will make your future decisions better.
Peter Drucker gets the credit for this idea:
“Checking the results of a decision against its expectations shows executives what their strengths are, where they need to improve, and where they lack knowledge or information.”