How to improve a second serve is an important question. Much will depend on where you are in the evolution of your serve. If you are just starting to get the ball in play, all you need to do to improve is get the ball in consistently without much regard to quality of stroke or use of proper grip. Practicing getting 10 serves in a row on the duce and ad side will improve your second service consistency. But to develop a quality second serve correct technique and proper grip is essential. If you have developed strong technique and mastered the service grip using a Continental grip, developing a reliable spin serve that you can get in 90%+ of the time will be the key to having a better and more impactful second serve. At this level practice your serve by trying to hit 5 consecutive full swing serves in play on the duce and ad courts. Do this at least 5 different times or until you can consistently be successful. After 5 successful attempts, try to hit 7 consecutive full swing serves in play 5 different times or until you are consistently successful. After completing 7 try to hit 10 consecutive serves in play. Once you have completed 5, 7 and 10 in a row, you will now own a very dependable and impactful full swing second serve. Give this a try, you won't regret it!