Number one is to work fast. Once you've made your pitch, get the ball, get back up on the rubber, go through your stretch sequence (or windup) again, and pitch the ball. The faster that you work, the more engaged your defense is, the less time they have to focus, and the shorter the game will be. Your team's performance will go up if you work fast.
Number two is to make sure that you are pitching to contact. Your job as a pitcher is to throw the ball into the strike zone and let the batter hit the ball. You have eight defenders on the baseball diamond to assist you in making an out, nine including yourself. Walks, hit by pitches, free bases, balks, and those kinds of things don’t give your team the opportunity to play defense. If you let the batter put the ball in play you have done your j
ob. You cannot control if your defense helps you out but you can control letting them hit the ball. Sandy Koufax said “I became a good pitcher when I stopped trying to throw the ball past batters and decided to let them hit it”.
Number three is to mix up your looks and the timing of your leg kick when you're pitching from the stretch with runners on base. If there is a runner on base, sometimes you should look once and then pitch the ball, sometimes you should look twice and then pitch the ball, sometimes you should look three times and then pitch the ball, and sometimes you shouldn’t look at all before pitching the ball. With the leg kick sometimes you come set and lift your leg after a one second count, sometimes it's on a two second count, sometimes it's on a three second count, and maybe you hold it for a little bit longer. By mixing up your looks and the timing of your leg kick when you pitch it's going to be very difficult for the base runners to get a good jump when stealing or base running.
Number four is to throw bullpens with batters, parents, coaches, screens, or cardboard boxes in the batter's box to get used to pitching in a game where there is a hitter in the box. Pitching in a game is completely different than in a bullpen without a batter. In a bullpen there is no pressure without a batter in the box, it’s not game-like, and it doesn't matter if you miss the target. Get comfortable pitching with batters in the batter’s box
Number five is that when you're starting out as a pitcher and you're a beginner, don't even worry about the base runners. If you work fast and pitch to contact you are doing your job. At younger and inexperienced levels, it's really tough for catchers to throw people out when they steal anyways. You will get out of innings much faster and have more success if you're 100 % focused on your job, which is throwing strikes to the batter.