Learning a piece of music successfully requires avoiding mistakes in practice. How we practice is how we learn, and how we learn is how we perform. If we make mistakes in practice, we teach ourselves to make mistakes in performance. It’s a simple equation.
What exactly is a mistake? Mistakes are more than just wrong notes. We may be dealing with mere semantics here, but it would be possible to call anything that is not exactly what you want a mistake. The slightest imperfection of rhythm, voicing, articulation, dynamics—all of this could be considered a mistake. I think such a strict definition would exceed its usefulness.
Even wrong notes are not created equal. Accidentally brushing against an adjacent key in a complex piano piece and playing a wrong note because you forget the right one are two entirely different types of mistakes. Both may be undesirable, but the first one may (or may not) be considered merely incidental while the second reveals an underlying oversight in the learning process.
Mastery is a process of refinement. The process of learning a new piece and the process of becoming a better musician are both ones of refinement. What may be considered successful in the beginning stages might be considered unsuccessful or unacceptable in later phases of mastery, either of a piece or of the instrument itself. Thus, what a beginner might legitimately consider accurate might for a professional count as a glaring mistake. “Mistakes” are therefore a moving target in the process of continual refinement.
While I encourage students to strive to get details of articulation, phrasing, dynamics and expression right from the beginning, obviously this is not always possible. As we study a piece, new interpretive possibilities and decisions open up to us.
Hierarchy of Musical Devices
There is, I believe, a hierarchy of musical devices in terms of our ability to change them after the fact:
This means that, in general, it is easier to change dynamics than it is to change articulation, and easier to change articulation than fingering. (Actually, changing fingering often automatically changes articulation too.) These are generalizations drawn from my experience. They may differ from one piece to another and are intended as a guideline.
Mistakes of rhythm are often particularly hard to correct, even more so than the actual notes. This is why I almost always work on rhythm first when teaching students a new piece. Rhythm is the backbone, the framework upon which the notes are placed. Mistakes of rhythm and timing are particularly insidious. Once a rhythmic habit is formed for a given piece or passage, it is exceedingly difficult to undo. Focus, therefore, on accurate rhythm first.
In my experience, fingering is more often than not even more difficult to change than a wrong note. This is why I always decide on fingerings—and write them in the score—as the starting point for learning any new piece I play. Importantly, with each movement of practice we are creating connections in the brain—what we (somewhat erroneously) call “muscle memory.” As essential as it is to the learning process to study a new piece from multiple angles, to abstract from playing itself to learn the rhythm, harmony and form in isolation, in the end it is above all our muscle memory, the kinesthetic feeling of the keys and the individual finger movements, that we rely on most. Strive to get your fingering right from the very beginning of learning a new piece.
A corollary to this rule is that transposed passages—in which a motive or melody is played in different keys—are often best played using a single fingering for all keys. The fingers have learned to associate a certain pattern to the motive or melody, and it tends to be easiest to maintain this fingering pattern in another key. (This is but a rule of thumb for which there are any number of exceptions.)
The notes themselves are the next level down in the hierarchy. Mistakes of notes are also very difficult to correct. Once a wrong note has been learned, it remains a part of the musical memory. Even a corrected note often brings with it a hesitation in performance, a sudden moment of uncertainty.
Articulation, as mentioned, is closely related to fingering. Try any contrapuntal passage, such as a two- or three-part invention by Bach, and articulate the subject in a different way. Let’s take the opening of Invention No. 1 as an example:
One articulation that could work well on the modern piano is this:
Once you’ve practiced playing it with this articulation, try changing to this one:
You’ll almost certainly find that it is inordinately difficult! This is why articulation is next in the hierarchy of learning and “mistakes.” Take special care to achieve the most musical and natural articulation from the very start of the learning process, as this is very difficult to change after the fact.
Dynamics are actually relatively easy to change. Most pianists can play a passage forte that they were playing piano or vice versa without too much trouble. Exceptions are highly technical passages that may be physically fatiguing to play loud, or fast, intricate passagework that should have been practiced pianissimo from the very beginning.