Speed and accuracy in your tennis serve is very important to be successful in a tennis game.  These two should complement for you to win in a competition.  Speed is useless if you don’t achieve accuracy and vice versa.  These days, having a fast tennis serve is very important to win in any tennis game.  But you need to always remember that when you’re trying too hard to serve fast, you tend to lose your energy and end up losing the game because your stamina gets lower.  Working your tennis serve and adding speed to it is possible even without exerting too much effort.  With constant practice, it will be easier for you to hit accurate shots most of the time.