When uncertain about a decision and you are aiming for an optimal outcome, Hastie and Dawes (2009), suggest that the choice be 1) based on your current assets (money, physiological state, psychological capacities, relationships, and feelings). 2) It is based on the possible consequences of the choice. 3) When the consequences are uncertain, their likelihood is evaluated using the basic rules of probability theory. 4) It is a choice that is adaptive to the constraints of those probabilities and the values or satisfactions associated with each of the possible consequences of the choice.
As for some of the mechanisms at play when making a decision the authors provide some advice, such as focusing on the future and not the past (sunk costs), avoiding cohesive conclusions based on random data or what you "know" (texas sharpshooter and conjunction fallacies, respectively). They also point out that fast somatic markers (emotion, feeling, mood, and evaluation) typically shrink large choice sets, which contain fewer options but allow a more thoughtful cost-benefit evaluation. They use overemphasized happiness as an example of this being a bad idea and suggest taking a more thorough look at other aspects of a decision. Along with that they also recommend spelling out many of the relevant events and really thinking through the "reasons for" and "reasons against" the occurrence of each event which can help increase the quality of judgments under ignorance.
They also list some common decision-making procedures that have no relation to rational choice. 1) Habit, or choosing what we had chosen before. 2) Conformity, or making the choice you think most other people would make. 3) religious principles or cultural mandates, choosing as we have been taught by our parents and authorities.
There is also Kahneman (2011), who found that our brain has two modes one really fast and the other slow and deliberate, we tend to rely on the fast mode more than we should in decision making and the many bias and heuristics that come with faster choices can make us more confident in our decision-making but may not give us the most optimal outcome.
The two references provided overlap and seem to work off of each other in one way or another. They both come to the conclusion that optimal decision making is made more deliberately than based on some of the fallacies and biases that we tend to rely on for quick choices in our day-to-day. None the less, they do provide excellent examples of understanding and knowledge of how to deal with uncertainty.
Hastie, R., & Dawes, R. M. (2009). Rational choice in an uncertain world: The psychology of judgment and decision making. Sage Publications.
Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux.