I'm a junior player who is absolutely obsessed with playing tennis. I take private lessons and my teacher has developed my first serve to be fast and flat. For my second he wanted more spin but I couldn't do that with my continental so he switched me more to an eastern. It seemed to work well but now I serve long on almost every second serve. Any tips on perhaps learning a kick/topspin serve or ways to hit my slice with more pace (my partners eat it up) and to keep it going in. Thanks!