The two most important things to do in subgun match is, one, don't wait for the steel to fall. Most steel targets, especially being hit with 9mm, will have a half second between when they are hit and when they actually fall. Many inexperienced competitors will aim, shoot, wait for the steel to fall, then aim at the next target. Experienced competitors will, aim, shoot, and go to the next target. If they missed something, they will go back for the miss before leaving that shooting position. Waiting to see the steel fall adds time.
Second, try to plan mag changes while moving and practice your mag changes on the move. If you only used five rounds at the first array, change to a fresh mag while going to the second array. If you need one more round at the second array of targets because you didn't change mags, you will be standing in front of targets with an empty gun. At an Indiana State match, the difference between first and third was three seconds. I consider a five second mag change to be competitive. In that particular match, an extra mag change for the winner would place him fifth. It is important to plan your mag changes. Standing in front of targets, changing your mag will tend to keep you off the podium. There was a thread here talking about subgun competition a couple of years ago. Maybe someone will be able to find it. Good luck with your competition endeavors.
Scott