Paddle Type
There are many different paddle types that vary in size, design and weight. Depending on who the paddle is for can determine the optimal paddle type. If it is for a child, plastic paddles can sometimes be better, as they are lighter and prevent the arms from getting tired more quickly. For adults, wood paddles are stronger and slightly heavier, allowing better control while playing.
Center Hits
Although there is no standard set of rules---other than hitting the ball as much and for as long as you can---there are still specific rules and tips that promote the player to hit the ball more efficiently. By striking the ball in the center of the paddle, the player will have a much easier time playing, as strikes on the edges will promote the angle in the paddle to shift, thereby making it more difficult to make the next shot level.
String Length
As the game is played by an assortment of ages, the string length can be the determining factor of success. Shorter strings are much simpler to hit; therefore, it is recommended to use paddles with shorter strings---especially in the beginning while learning---and then lengthen the string as you become better at the game.
Practice
The only true and definite way to become better at paddle ball is to practice frequently. The game depends on eye and hand coordination, which requires strong muscle memory. Muscles are trained to perform a certain movement through repetitive action; therefore, chances are the person who paddles the best will be the person who paddles the most.