A few months later, I had to learn a difficult free accompaniment for a Christmas hymn sing, and started slowly with a metronome. I worked diligently and patiently and was able to play the two verses of free accompaniment with confidence and few to no mistakes.
I've been working up a piece for an Easter hymn sing that's very, very difficult. First I practiced the manuals alone with a metronome. I started with the sixteenth note at 50 bpm. When I began to feel comfortable with the manuals and had worked it up to about double that tempo, I began practicing the pedals with the right hand, then the left hand, then combined. I think I had to start the tempo even slower than the sixteenth note at 50 bpm.
It's been a very slow process, but it's the only way I'd be able to learn this piece. No matter how hard the piece is, it can be conquered, slowly and steadily.
I'm currently playing the piece with the sixteenth note at 200 bpm and am dropping to the eighth note at 100 bpm. I only have to double my speed one more time and I'll have it!
Pardon my extraneous movements (I'm working on them), but here is my progress so far:
I've learned that taking the time to practice and learn a piece correctly doesn't really take any more time than practicing too fast and learning mistakes that need to be unlearned. The problem with my soprano solo was that I was trying to flub my way through it, and it backfired on me.
Practicing with a metronome offers measured improvement. Today I increased a piece 20 bpm in one short practice session. When I get discouraged with how little time I feel I've had to practice, I can actually see how far I've come. A metronome allows me to make good progress in short spurts of practice time.
Give it a try!