Planning your strategy after knowing what your knock card is extremely important. Before you even pick up a card, you should know generally if you need to play offensively or defensively. You should also know exactly what you should hold in your hand before you go any further. This could not be more important then when the knock card is an Ace and you need to play to gin.
Melding all 10 cards can be difficult but not impossible, especially if you know where you need to begin. You already know that you can do this by making 3 three-card melds, and 1 four-card melds. This is the most usual way in which people will reach gin. It is wise when considering this that you also take into account that it is easier to reach gin by melding runs that have the ability to be added onto. For example, it is easier to go gin if you have a 9, 10, J, instead of 3 Jacks.
Since it takes much longer to develop 10 melded cards than developing 6 melded cards, you must play the hand with considerably more care then if you were playing with a high knock card. Your concern should be to throw your opponent relatively safe discards during the play of the hand so that you have the time to develop your hand. An even more important strategy is to get your opponent to take certain cards which you want him to pick because they will give him dead runs.
For example, if you are holding the K ♦, Q ♦, and J ♦, and the Q ♠, and J ♠ have already been played then the best card to see him pick would be a K ♠ because it is a dead run. He would never be able to use it because you already have the potential fourth K and there is no sequence he could use the K ♠ with. The more dead runs you can get your opponent to take or hold, the more you are reducing his opportunities to win while at the same time increasing your own by giving you more time and more cards you actually need. Just make sure that when you are giving your opponent dead runs, that you are using the odd card to form a meld of your own, and aren’t just holding it for no reason. For the same reason he can’t win, you don’t want to hold onto two of your opponents cards unless they are in melds, because then you can’t win.
In any game of gin, people want to be in the position of giving your partner dead cards, but it may not always be possible if you are playing another expert player. It is also not likely to do it on a continual basis, but if the opportunity does arise, make sure you are aware of how to take advantage of it.