Having good decision-making abilities is an alchemy of sorts—a combination of nurture and nature. People who are naturally "good" tend to make good decisions simply because they inherently wish to see good outcomes—everyone makes mistakes of course, but that's not a bad rule of thumb.
However, good decision-making is also something that can be—and in police training must be—developed and improved upon. There are a few schools of thought on this.
One is Rational Choice Theory (RCT) in which people are taught to gather all available information, make a list of possible actionable options, and compare those choices against a set of measurable parameters (values). Another is Recognition-Primed Decision-Making (RPD) in which people compare possible actions against known outcomes from past experiences (either personal experience or historical example).
Opportunities to develop decision-making are abundant in police training. Most notably, decision-making is the focus during use-of-force scenarios and emergency vehicle operations training, but there are also the subtle moments trainers can use to emphasize making well-informed and well-intentioned decisions.
For example, the de-escalation of a potentially volatile situation is often the outcome of a series of informed decisions based on using active listening to gather intelligence, and then applying analytical thinking to the problem. Active listening, analytical thinking, and problem solving are all skills that can be taught and improved upon through training.