For improvisation: can you play by ear? For myself, I was surprised to find that this is a learnable skill.

When I was in music school, I discovered that I had no idea about this. If I heard in my head what should come next, I had no idea how to play it; and if I thought of a theoretical chord progression or modulation and played it, the sounds that came out were not what I had wanted.

I remember doing two exercises, which were helpful in learning to play the harmonies that I wanted. One is to take a chord progression that has struck your fancy, and to play it in all 12 keys, until you have mastered it. The other is to play all successions of two chords, and listen carefully to how they sound. For example, play C major and try how it sounds followed by all 12 possible minor chords. Or try C minor and try how it sounds followed by all 12 possible major chords. Some of the permutations will match up with characteristic gestures that are already in your aural memory, so note those for future use.

My organ improvising was all self-taught. The easiest is to play softly things that are in imitation of accompanied chant. Then you can go from there.

One thing to keep in mind about improvising: once you have played a note, you cannot undo it, it has become part of the piece you are improvising. That means that the only way to atone for a wrong note is to alter what comes after to make it fit. There is a story about Dupre, he was playing a Bach fugue, and an "A" pipe began to cipher. He improvised the ending of the fugue to close in A minor, pianissimo. So any mistake can be make to work. This is a consoling thought when applied to life.

Have you a teacher?

To start with, just try noodling around.

Take a melody you know really well and see how many different ways you can change the accompaniment.

Theme and variations (of every kind/composer) are great things to imitate as they open your eyes to the myriad of ways a single theme can be treated. Then you can take a different theme of your choosing and try doing each style of variation used by your model yourself on your own chosen theme.

There are also a few method books about improvisation around if you do some yahoogling. I've seen a few but never used them.

The biggest help for me was just spending time improvising every day. When I was in undergrad, I would probably spend a full hour of my 2-3 hour daily practice just improvising. Now that I do not spend that much time playing that way, I find improvisation more difficult than I used to, although I still do it daily. All that is to say, it is a skill that needs to be practiced and cultivated.

I also second the suggestion of trying to play by ear. That, honestly, is probably step one. You need to be able to tell your hands how to do what you hear in your head. You can have all the ideas in the world, but if you don't know how to make your fingers and feet do what you hear, it's all moot unless you're sitting at a piano composing. Get that first step down first, and then the rest will flow naturally.

Dupre: Method of improvisation. Best out there and rather thorough. Boring at the beginning but you need to do it.

Thanks, everyone. I do not have a teacher, nor am I a member of the AGO; I inherited the organist position a couple years ago and have never had any formal lessons. I'm excited to spend time just fooling around with some hymn tunes.