The safest way to warm up before playing tennis seems to be to have both players stand on the service line and tap the ball on one bounce back and forth. This allows you to warm up your hand/eye coordination and find good contact without risking a painful mishit with a full swing.
For some players this is not easy. Many players today are taught to take a full swing the
first time they step onto the court. If your opponent prefers too warm up from the baseline, be sure to swing slowly and watch the ball closely to avoid mishitting the ball with a full swing. It is best not to do anything quickly until you have broken a sweat. Overdressing at the start helps. Some like to jog a few laps around the court. Some like to take a few practice swings.
When you do move back and take full swings, start out with a steady top spin balls that land close to your partner/opponent. If you are playing a match, look out for which side does your opponent step around. This usually tells you which one is the weaker side. Hit a few more shots to the backhand side and the forehand side to see which they prefer more. One important note is to remember to take a few at net to warm up as well. The best is to warm up before getting to your match.
In addition, remember to do a few laps before the match in order to warm up the legs. If you want to channel what Nadal does, run and touch the baseline side to side.
Hard Court vs Clay Court
Many of the great players came from the American hard courts. Often this was due to their learning to play an attacking game. The true and fast bounces combined with the firm footing allowed for building powerful groundstrokes and serves as well as point ending volleys and
One strategy on hard courts is to hit deep groundstrokes until you get a short ball which you hit deep and follow to the net where you can end the point with an angled volley.
Another is to serve and move forward looking for a ball to volley. Another is to attack your opponent’s short shot either by hitting a winner or moving in toward the net.
In the past North Americans played on hard courts (asphalt or cement) whereas Europeans and South Americans played on clay. There are clay courts in the U.S. But they are usually green and very different from the red clay/ The red clay is very dusty and slippery.
The biggest problem for hard court players is stopping on a clay court. On a hard court when you want to stop you plant your outside foot and you will stop moving to the side or you plant both feet and you stop moving forward. In both cases on a red clay court you will slide before coming to a stop. The reason for stopping is to change direction. On a clay court if you want to stop, hit the ball, then move to the center, you must slide to a stop first. This takes a lot of practice. If you are serving and volleying, you may as well forget about the split step and run to where you think the receiver is returning the ball.
Another problem is the bad bounces. Every time you slide you leave a hole in the clay.When the ball hits the hole the ball bounces funny. An experienced clay court player will smooth it out before the next point.