In my reading into the OODA loop, orientation is the most important part of the loop. According to Boyd:
"Orientation is the Schwerpunkt. It shapes the way we interact with the environment - hence orientation shapes the way we observe, the way we decide, the way we act."
In order to get better at orientation, one needs to accumulate mental models, or views/frameworks of how the world works. The more mental models, the more viewpoints we have to evaluate reality, and the better we can make the correct decision to act.
Thus in Boyd's theory, in order to make better decisions, one needs to increase one's mental models.