Remarks from the rules:

When Discarding, players should not forget that discarding a complete suit to have the best discarding possibilities could also mean being left with one "lone" 7 and/or one 9 and/or one 10 from another player's discarded pile!

To avoid winning a trick, players are often tempted to play lower ranking cards than those played by previous players. Players should know to "build up a few points" in the first rounds when the stakes are low to then get rid of their highest ranking cards and keep the lower ranking cards for the following rounds. This can even be an advantage for the last player as he clearly knows the ranking of the cards.