The thing to remember is, no matter how good you think you are, there's always someone who'll show up at the match and kick your butt.
My philosophy: When I go to the range, I have just one purpose in mind. I work on one task; first shot from the draw, transitions, groups, fast DA on multiple targets, adjusting my grip so I can find the damn dot instantly, whatever. I’m a pretty serious competitor and I’m about to turn 67, so I have to stay on top of my game.
Of course, sometimes I just haul out my Garand or SKS or AR-15 Close-Range-Zombie-Gun and have fun.
Use a timer. Keep a shooting log. If you modify your pistol, write down what you did. Did it help?