An outcome can make a past decision look more obvious than it felt at the time. Keep a short record before the result is known. The record should preserve the situation, the available options and the reason for choosing one.
Write down the assumptions carrying the decision. Which facts are verified? Which estimates could be wrong? What would make the chosen option unsuitable? Include a point at which reviewing the decision would still be useful.
Keep it proportionate
For a fictional choice between two workshop formats, the record might identify available preparation time, learner needs and the cost of changing later. A paragraph can be enough. The purpose is to preserve reasoning, not to create a defence brief for every everyday choice.
When the outcome arrives, compare it with the assumptions. An unsuccessful outcome may follow a reasonable decision under uncertainty. A successful outcome may depend on favourable circumstances the original reasoning failed to anticipate.
Improve the next judgement
Look for one change in how you gathered information or weighed alternatives. Did you ask someone who would use the result? Did you overlook a dependency? Did a reversible choice receive more analysis than it deserved?
Keep decision records for matters where the learning is worth the effort. Over time, the collection becomes a record of how your thinking changes. That is more useful than remembering only the predictions that happened to come true.