This improves your point count and brings you closer to the goal of knocking.

Though the general rules of Gin-Rummy are simple - take a card, discard a card - but gin rummy is far more complex to learn, is more strategic game than most people realize. Below I have listed the "10 commandments" of Gin-Rummy strategy:
1. Play to knock As quickly as possible, develop a hand consisting of melds, a triangle, and a knock cache. When you hit one of the four cards needed to create a meld from the triangle, you can knock. When playing Oklahoma, you should evaluate this rule based on the knock card; the closer to ten it is, the more applicable the rule.
2. If you're going to knock, knock! If you are not playing to gin, knock as soon as possible. Every delay gives your opponent a chance to beat you to the knock. This is the most commonly violated rule in gin rummy (as well as in life generally).
3. Always pick up a meld If your opponent's discard makes or increases a meld in your hand, pick it up. This improves your point count and brings you closer to the goal of knocking. Of course, you must weigh this rule appropriately if you have a possible draw-to-gin.
4. Don't pick up strays If your opponent's discard does not make or increase a meld in your hand, don't pick it up.Your odds are better picking from the stock.
5. Don't help your opponent If you know that a card will make or increase one of your opponent's melds, keep it in your hand. An exception occurs when the only choice is to give your opponent a new meld.
6. Don't try to help your opponent If you think that a card might make or increase a meld for your opponent, keep it in your hand. If you have a choice of discards, choose the one with the fewest number of hits.
7. Throw the big bombs early If you start with four (or more) unmatched 10-point cards in your hand, start discarding them immediately, regardless of the combination chances. It is good to keep one high-card triangle early on, but if it is still unfilled after six or seven draws, start discarding it safely. More points are lost more quickly by disregarding this rule than by any other failing.
8. Sweep the floor This is an extension of rules (1) and (3). If you consider your knock cache a meld, then it is prudent to pick up a discard to fill it.
9. A tie is better than a loss In the end game, thoughtful play is extremely valuable. You have more information about your opponent's hand, and can calculate the odds of any discard filling their needs. For the last few draws, your goal is to prevent your opponent from winning the hand. Win if you can, but play your discards completely safely.
10. An undercut is better than getting ginned If you are faced with the choice of the risk of an undercut on your knock or the risk of discarding a card that gives your opponent gin, knock. Your opponent is more likely to gin than they are to undercut, and the loss when they gin is much greater than the loss when they undercut.

gin rummy