What's the best head size for a tennis racquet?
A larger head offers more power, usually a more open string pattern for slightly better spin , a larger sweet spot , and more resistance to twisting for an off-center hit at any given distance
A smaller head offers more control , more maneuverability at a given weight and balance, less maximum twisting because a ball that would hit the outer edges of a large head will simply miss a smaller one
Larger, "oversize" heads are generally the best choice for beginners. Most advanced players prefer "mid-size" heads.

Where should I add weight to my tennis racquet for more power?
Adding weight (usually as lead tape) to any part of your racquet will increase its power to some extent, but you'll get more power per added weight the farther toward the tip of the racquet it is placed. The sweet spot will move toward the added weight. While you'll get the most added power per weight by placing the weight at the racquet's tip, you'll get the added benefit of more stability in proportion to how far you move the weights out toward the sides of the racquet.

What is shock in a tennis racquet?
Shock is the initial force transmitted to your hand and arm from the ball's impact with the racquet face. It is an important factor in causing many types of cumulative injuries. Shock can be reduced by lowering string tension and increasing racquet weight. Contrary to much of the popular literature, stiffer frames also reduce shock.

What is meant by a "more forgiving" tennis racquet?
A racquet is often called forgiving if, on off-center hits, it transmits less shock to your arm or produces less unpredictability in the direction of the ball's rebound. A flexible racquet is more forgiving to your arm, whereas a stiffer one is more forgiving to your shot, so the term is sometimes used in contradictory senses. A racquet with more stability, however, is more forgiving in both senses.

What makes a tennis racquet more powerful?

• Several factors increase the power of a racquet's frame, listed from most to least important.
• larger head size
• greater stiffness through materials and profile
• greater weight
• more weight toward the head (head-heavy balance)
• more length
  

What gives a tennis racquet more control?
A smaller head, stiffer frame, and tighter strings all favor control. The combination of a very stiff frame and tight strings is tough on the arm, though, so many advanced racquets have medium-stiff frames that moderate the harshness of tight strings.

What is the best material for a tennis racquet?
Because of its high stiffness-to-weight ratio, graphite is the preferred frame material in the better racquets. The graphite used in racquet frames is not the true graphite you would find in a pencil, but a carbon fiber that adds stiffness and strength to the plastic resin with which it is mixed to form a frame. When a racquet is made of resin and graphite alone, it is called 100% graphite, even though it is at least 40% resin. If other materials are used, the frame is called a composite. The quality of a composite frame depends largely on the amount of graphite. Some composites are too flexible for advanced players.

What is the ideal weight for a tennis racquet?
The ideal racquet weight depends on how you play. You can get a recommedation for your playing style here. Generally, racquets weighing less than 10 ounces don't make sense for any adult, because they're too light to protect your arm from even the lighter shocks of infrequent doubles play. As long as you can wield it, more weight is advantageous, but most players find more than 12 ounces too unwieldy.

Are extra-long tennis racquets better?
The pros and cons of extra length are much debated. As length increases, so does power, but, some argue, at too much cost in maneuverability. A longer racquet is most often recommended to shorter players, who will benefit most on the serve, both because of the extra reach and because the serve swing pivots sharply at the wrist, making the swing radius shorter. With a short swing radius, the extra racquet length make a larger difference, proportionally, so players whose groundstrokes pivot more at the wrist will also get the most added power from extra racquet length. Racquets up to an inch overlong are fairly popular, but racquets with more than an inch of extra length have almost disappeared from the market, probably because players found that much length too unwieldy.

What is the sweet spot on a tennis racquet?
Every racquet has three different sweet spots, but in a general sense, the sweet spot is the area of the string bed that produces the best combination of feel and power. The most powerful spot on the string bed is that with the greatest coefficient of restitution. The one with least vibration is found at the node of the first harmonic. The one with least shock is found at the center of percussion.

Will putting a vibration absorber in my strings protect my arm?
The high-frequency string and frame vibration that a vibration absorber eliminates might be annoying, but, unlike shock, it has little effect on your hand or arm.

Where should I add weight to a light, head-heavy racquet?
Adding weight to the handle of a light, head-heavy racquet is the best way to reduce shock without making the racquet feel much heavier. Most racquets allow you to place weights inside the handle, but you can use lead tape just below the throat on racquets that don't.

Where should I add weight to my racquet for more stability on off-center hits?
Imagine the head of your racquet as a clock face, with the tip at 12:00. Adding weight at 3:00 and 9:00 will give you the best gain in stability.

What's the ideal balance for a tennis racquet?
Racquet balance is a topic of some debate. Generally, heavier racquets tend to better protect the player's arm, and to make them more maneuverable, they are usually built head-light. Light racquets are usually balanced head-heavy in order to deliver a solid thump on the ball. The real debate centers on which balance, in the moderately heavy racquet weighing around 11 ounces, better protects the arm. Whether a player wants more maneuverability or more groundstroke solidity is a matter of personal preference, but the question of arm safety is more complicated.