Start with what the rules allow
Check which items you may take, whether any costs apply and what happens to the remaining selection. Different games use the same broad mechanism in different ways.
Look at contribution and fit
An item can provide an immediate benefit or complete a combination later. Compare that contribution with the items already available to you, rather than judging the new item in isolation.
Notice the opportunity cost
Choosing one item means leaving another. The relevant cost may be a missed combination, a later constraint or a useful option left for somebody else.
Avoid certainty about other players
You may see another player’s public position without knowing every objective or private card. Treat your explanation of their preference as a hypothesis unless the rules make it fully visible.
Review a choice in its original context
After the game, reconstruct what was known when you chose. An outcome that became obvious later may not have been predictable at the time.