A serve is made when there has been no fault on the point; a second serve occurs when there has already been one fault on the point. On a second serve, the server is in danger of losing the point if there is another fault.

The rules make no distinction between the first and second serve. However, the tactics used are different. The first serve is typically struck with the maximum power, skill, and deception the player is capable of with the aim of winning the point either outright or on the next stroke, by forcing the receiver into a disadvantageous position. The second serve is usually more conservative to avoid getting a double fault and is typically hit with less power or a higher curve. The second serves often have more topspin and kick on the ball.

There are two popular stances in the tennis serve: the platform stance and the pinpoint stance.

In the platform stance, the feet are kept about shoulder-width apart throughout the service, providing stable support and easy weight transfer from the back to the front foot. The hips rotate, and sometimes the back foot swings forward to complete the hip rotation.

In the pinpoint stance, the feet start apart, but as the serve unfolds, the back foot slides or steps forward until it is adjacent to or slightly behind the front foot. As a result, the feet provide a very small base of support and balance may be a problem.
The pinpoint serve provides better velocity, since the feet come together as a single unit, allowing them to push harder against the ground and gain more leg power. However, the center of gravity moves more than in the platform stance, so the player must have good body control in order to contact the ball consistently.

Players will sacrifice some power with the platform services, but their balance will be better so they should be more consistent. It's still possible to produce good power with the platform serve—some big servers, such as Milos Raonic and Roger Federer, use a variation of a platform stance.

The service each player uses will depend on their individual abilities and what they need the most—power or consistency. If they already have good body control but would like to produce extra power, they could try the pinpoint stance. If consistency is their problem, they can use the platform stance.
The platform stance and the pinpoint stance are closed stances. For a very long time, the use of an open stance to serve had been regarded as a sign of a tennis beginner. Things have changed in recent years. At the elite level, Venus Williams had used a semi-open stance to serve in the past (she went back to use a traditional closed stance and stayed to the old way currently). Beside Venus, Nikola Mektic and Viktor Troicki both have abandoned closed stance to use open stance to serve.

In the game of tennis, there are four commonly used serves: the "flat serve", the "slice serve", the "kick serve", and the "underhand serve". All of these serves are legal in professional and amateur play.

The term kick serve is ambiguous. It may be used as a synonym for the twist serve or the American twist. However, kick serve is commonly used to refer to any serve with heavy topspin or kick on it.

Servers can gain a tactical advantage by varying the type of serve and the ball's placement. The flat serve and slice serve are used primarily as first serves because they are more likely to yield an ace or force an error, although they require high accuracy. Second serves usually have slice, topspin or kick on them, which makes them less likely to land in the net or out of bounds. Kick serves also make a good change-up as a first serve.
A flat serve is hit with either a continental grip (holding the racket as if it were an axe), an Eastern backhand grip, or somewhere in between. The swing path goes directly toward the target at impact, which causes the ball to cut quickly through the air without spinning. Some professional players can hit flat serves at speeds near 150 miles per hour (240 km/h).

A flat serve must come close to the net therefore having a small margin for error. Therefore, flat serves are usually hit straight across the center, where the net is lowest. They are usually delivered as first serves, when the server does not risk a double fault. The ball is thrown straight above and slightly forward for the optimal serving point.
A slice serve is hit with a sidespin, which requires the server to brush the back of the ball toward their dominant side with the racket. It is commonly hit with the Continental grip or the Eastern backhand grip (using the forehand face of the racket). The ball is thrown slightly to the dominant side of the server then is struck laterally on the server's dominant side.

For a right-handed player, a sliced serve's sidespin causes the ball to curve leftward. When the ball bounces, it skids and curves farther leftward. The curve of a good slice serve can draw the receiver 10 feet (3.0 m) wide of the singles sideline to play the ball. Since a slice serve has little or no topspin on it, it cannot be aimed high over the net and has little margin for error. Therefore, it is generally used as a first serve. It can be used to ace the receiver, to draw the receiver out of position, or to "jam" the receiver with a serve curving sharply towards the receiver's body.

The reverse slice serve (or inside-out serve) is analogous to the screwball pitch in baseball. It is hit with the opposite spin of the slice serve. Servers must pronate their racket arm and sweep the racket across the body while striking the ball when hitting a reverse slice serve. Because the direction of spin applied is reversed relative to the standard slice serve, a reverse slice serve from a right-handed player will have the same motion as a slice serve from a left-handed player, and vice versa.

In professional and amateur tennis, the reverse slice serve is rarely used except as a novelty. As the word reverse is defined, one must hit opposite to the sid…

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