I don't shoot Bullseye, but I follow Tony's blog. He did a good job of summarizing the full article, but I recommend, as he did, that you read the whole thing. It starts on page 4 here. It doesn't matter what kind of shooting sport you are involved in, this is good advice.
Here's a quote. The bolded emphasis is mine.
LESSON 10—YOU NEVER SHOT YOUR BEST SCORE -- This lesson has to do with a mindset that real sports champions all seem to develop. It has to do with whether a record score is a mountain peak or a stepping stone on the way up to a mountain peak that one never quite reaches. It encompasses the idea that no matter how good a winning score or new record was, there are still ways to make that score even better. This was a lesson I unintentionally started to use early in my competition career. However, I didn’t understand it until much later. From the very beginning, I kept careful records in my “shooting diary.” As I recorded my scores I added pages in the back of the diary to list personal records in both practice and matches. This meant that every time I shot, I engaged in personal contests to improve those records. Of course there were practice sessions where I shifted the emphasis to experiments or work on a particular aspect of my technique or positions, but almost every training day included a competition with my personal records. Later when I was shooting with the Army International Team, the same coach who insisted that I analyze my bad shots also began to insist that I find things I could do better even after I won a big match or shot a new record. Yes, even when there was a new world record, there had to be things I could do better.