1. Play what you enjoy. This is probably the most important rule. You have to play, learn, practice, study and perform the pieces that you love. Live is short and there is only so much time in the day so you have to carefully think what you like best and play it.
Play only quality organ music which withstood the test of time. So much organ music has been written in the last 30 years or so and a substantial part of it is of low quality (especially in church music field). In general, when you look at the organ piece, see if it has all the features of the quality composition - harmonic, melodic, rhythmic integrity, and balanced formal design, among others.
Of course, if you are a student or your experience at the organ is limited, you have to play a wide variety of repertoire in order for your organ education to become complete. But even in this case try to pick pieces which are worth learning.
2. Enjoy what you play. This is the other side of this coin. You have to love, what you play, learn, practice, study and perform. Otherwise you will find difficult to be honest about it and your playing will not be passionate. You have to sincerely try to find all the strong artistic features of your piece and fully enjoy every minute you play it.
Remember, practice is a privilege, as my former organ professor Pamela Ruiter-Feenstra always says. Because of variety of reasons, many people who love organ playing have no practice possibilities and opportunities or their practice time is limited.
So if you are able to sit on the organ bench and practice, it should feel like a privilege to you. When you understand this, you will be grateful for short or long moments you are given on the organ bench. Such moments you will definitely enjoy.
Of course, you might have a question, like "what if I HAVE to play this composition which is not exactly my favorite?". You see, always try to see the features in your piece which you can learn from. I believe every piece has certain elements which you can appreciate.
Even if you have to play a low quality composition, ask yourself, "what makes this piece a low quality and uninteresting?" Then you can learn from it and try not to repeat the mistakes this particular composer have done when you create your own music (yes, you should compose music - study the existing compositions and try your hand at it, it's fun and you will learn a lot in the process).
As you can see, passionate organ playing shows. Play what you enjoy and enjoy what you play. Then your playing will change lives.
By the way, do you want to learn my special powerful techniques which help me to master any piece of organ music up to 10 times faster? If so, download my FREE Organ Practice Guide.
Or if you really want to learn to play any organ composition at sight fluently and without mistakes while working only 15 minutes a day, check out my systematic master course in Organ Sight-Reading.