There's a lot to be said about this subject, but more and more I'm aware of the important mental aspects of piano technique.
For instance, do you find that you constantly stop and start in your playing? This could be because you don't "chunk" enough. Chunking means grouping information so that your mind retrieves it in groups.
As a simplified example, if you've got a measure with 20 notes in it, you'd have to think and execute 20 separate things to get through the measure. But if you can group those notes into 5 groups of 4, you'd only have to execute 5 commands to get through the measure. Thats a quarter of the mental workload!
A lot of what allows a seasoned pianist to play incredibly complex works is that he's practiced so many different patterns that he's able to chunk almost anything efficiently.
There are a lot of ways to work on your "chunking abilities" but one of the best is very simple; although it involves quite a bit of self-control and concentration. It is simply this: pause every few notes and think ahead. Can you think through the next few notes as "one" thing instead of several separate notes? If not, can you repeat them until you can? Obviously if the next few notes are part of some chord or repeating pattern this task is easier, but they don't have to be. Any notes can be "chunked" as long as you practice them enough.
This is such a broad subject. I'm sure I'll have more to say on it. Hopefully this makes some sense!Want to learn piano but don't know where to start? I've taught hundreds of happy students! Click here for my free beginner lesson course.