Record the available alternatives
Write down the choices you could actually make, including their costs and restrictions. An imagined option that was illegal or unavailable is not a fair comparison.
Describe the expectation
What did you think the move would improve? State the horizon and the information you relied on. A short concrete reason is more useful than calling the move clever or foolish.
Trace what changed
A later event may alter the value of an earlier decision. Identify the new information or changed position before assigning all responsibility to the original choice.
Ask another player what they saw
A different perspective can reveal an option you missed. Invite the explanation without turning the conversation into a demand that someone defend every move.
Choose one question for next time
A focused question is easier to carry into another play than a long list of corrections. Look for a recurring decision rather than trying to script an entire game.