Purchase the basketball shoe Stick'um mat so that you and the rest of your team can step on it before entering the court. This will increase traction and eliminate slipping. Make sure to restep on the sticky mat during every timeout because the Stick'um does wear off during the game.
Use the "B-Sharp Traction Action" to increase the grip on your shoes. You simply soak a towel in this liquid and then step on it before entering the court. This product is guaranteed to work. However, it is known to wear off much quicker than the the Stick'um mats.
Increase the grip on your basketball shoes quickly in the middle of a game by using your tongue. It may sound odd, but wiping your hand on your tongue and then wiping that hand on the bottom of your shoes does work to increase traction. You may not notice it, but if you watch any professional basketball game you can usually spot multiple players doing this throughout the game. This does not work as well as the Stick'um or B-Sharp product.
Clean the bottoms of your shoes after every game, and at halftime if at all possible. The basketball court attracts dirt and dust and then attaches it to the bottom of your shoes, which reduces traction. Cleaning the bottoms of your shoes regularly will prevent dust and dirt from building up.
Purchase a style of basketball shoes specifically designed to increase traction. Most players buy their shoes for the style first and foremost and never look at the types of soles their shoes have. Buying a basketball shoe that does not have a flat smooth sole will increase the traction without having to use any of the other type of trick to increase your grip.