Knock early! It might be tempting to hold out for that gin bonus, but if you can knock early in the game and catch your opponent with a lot of high-valued cards in his hand, you can earn a whole bunch of points.
Try to keep track of discards. You don’t want to be in a situation where you’re waiting for a card that was discarded several turns ago.
Notice what cards your opponent is drawing from the discard pile. That will give you a clue as to what kinds of melds he or she is making, and might prevent you from handing over the game-winning card.
If you’re trying to make runs, it’s better to have two consecutive cards that need an "end" instead of two spaced out cards that are looking for a "middle." For example, having a 4 and 5 of the same suit is better than having a 3 and 5, because there are two cards that can form a run with the first case (either a 3 or a 6), but there’s only one card that can form a run with the second case (the 4).
Often, it’s easier to knock with two larger melds and some low cards than it is to knock with three melds.
Some people prefer getting rid of high cards as soon as possible, so they don’t end up with lots of points in their hand. On the other hand, if you have, say, a pair of queens and are playing against somebody who likes to discard their high cards, it might be worth holding on to them and hoping your opponent discards another queen.
Remember, you can arrange cards in your hand by dragging them left and right. This will help you plan your hand better.
