There are some very good suggestions on this thread, but another vantage point may help. Think of terms of athletics. Why does a particular athlete repeatedly make the same mistakes or suffer the same injuries? Similarly, why do some others with less talent find a way to win?
1.) Some fail in an activity within the game that uses a part of their bodies that is weak, leading to injury or a body foul. They need to work outside the game to strengthen that part of themselves. They also need to avoid overstraining the weak parts of their bodies.
2.) Some fail at an activity that was learned incorrectly and practiced incorrectly. This athlete can change only with difficulty, by consistent correct practice.
3.) Some athletes persist in a particular style of game, even though his or her strengths and weaknesses won’t support it. These athletes need outside criticism and coaching, as well as a willingness to leave behind their preferred style of play.
4.) Some athletes have not learned how to defend against a certain move of the opponent without commiting a certain foul, and the opponent knows it… thus the opponent has no need to change their plan of attack. These athletes need to consider a new game plan.
5.) Likewise, some athletes cede advantage by not knowing their opponent’s abilities and tactics, thus letting the opponent control the game.
6.) Some athletes do not give themselves enough rest or proper nutrition prior to competition. It is impossible for them to rise to the occasion, no matter how much other preparation they have done… or how well-rested and well-fed they were last week or last month.
And so on…
Most athletes are not granted the particular talent to reach perfection in every aspect of his or her game… these athletes just have to do the best they can to improve and then strategize so as to keep that part of the game from gaining undo importance in the final outcome, whenever possible. The champions win by keeping their eye on the prize, by using every opportunity to gain overall advantage, by keeping themselves “coachable”, and by never, ever giving up until the final buzzer sounds. In doing that, 99.9% of what leads to their win is done on the practice field… that is, when no one is there to cheer or hand out points, and when their opponent’s efforts are out of sight.
I think that within the spiritual life, as within athletics, we need to recognize that although we strive to improve, we aren’t going to reach perfection in our every move. That doesn’t mean it isn’t worth doing, only that we will have limited success. In fact, it is axiomatic in athletics that athletes must dwell on past mistakes only long enough to address them. After that, they have to put them in the past. (Doesn’t the sacrament of reconciliation just keep making more and more sense?)
What matters is that our success is sufficient to gain the prize. To do this, our striving has to include nutrition and self-care, persistence, self-discipline, outside direction, trust in the source of that direction, and an openness to change in order to submit to that direction. Sitting and wishing we were better won’t cut it. “Run so as to win!”