First check whether a move is legal. Then ask what it reveals or makes available. Use only visible information when planning. An unknown face-down card is not a card you may choose or promise to uncover.
Worked example
In the picture, moving red 4 of diamonds from column 1 onto black 5 of clubs in column 2 is legal. It removes the only face-up card from column 1. The hidden card beneath it turns up automatically, giving new information.
Useful Does Not Mean Guaranteed
Another legal choice moves black 5 of clubs from column 2 onto red 6 of diamonds in column 3. It empties column 2 but uncovers no hidden card. The first move reveals information now; the second creates a king space. Which is useful depends on the rest of the deal. Neither choice proves a win. The dotted card in the picture has an unknown rank.