I finally got around to listening to this interview of Mark Forster, a UK productivity expert. There weren't any revolutionary ideas, but I did find a few things interesting.
Mark Forster says that projects are really commitments. A commitment is not just a collection of promises to do things, but also a promise not to do others. For instance, if you are married, you promise to be faithful to your spouse and not chase other men/women.
Mark states that when you are stuck in your progress, the problem is often some rate limiting step and you have to apply overwhelming force ("overlearning") to fix the rate limiting step, so that you can move on. The example he gives is Morse code operators. When training these operators, it was found that they would often get stuck at a certain translating speed, no matter how much they practiced. The solution was to have the trainees practice the difficult letters. After they learned how to translate all letters equally well, they were able to improve their speed overall.
Finally, Mark emphasized the principle of "little and often." Your mind needs time to make connections. It is much better to spend 1 hour practicing the piano per day than to practice for 6 hours before your lesson. You often gain a new perspective when you come back to something later.