If you want to eliminate hindsight bias, write down some reasons that you think justify your judgment.

Those who consider the likelihood of an event after it has occurred exaggerate their likelihood of having been able to predict that event in advance. We attempted to eliminate this hindsight bias among 194 neuropsychologists. Foresight subjects read a case history and were asked to estimate the probability of three different diagnoses. Subjects in each of the three hindsight groups were told that one of the three diagnoses was correct and were asked to state what probability they would have assigned to each diagnosis if they were making the original diagnosis. Foresight-reasons and hindsight-reasons subjects performed the same task as their foresight and hindsight counterparts, except they had to list one reason why each of the possible diagnoses might be correct. The frequency of subjects succumbing to the hindsight bias was lower in the hindsight-reasons groups than in the hindsight groups not asked to list reasons.

ARKES, H.R., et al., 1988. Eliminating the hindsight bias. Journal of applied psychology.