Slow practice is undoubtedly the basis for quick playing; but quick playing is not an immediate result of slow practice. Quick playing must be tried from time to time, with increasing frequency and heightened speed, even at a temporary loss of clearness. This loss is easily regained by subsequent returns to slow practice. After all, we must first learn to think quickly through the course of a piece before we can play it quickly, and this mental endeavour, too, will be greatly aided by occasional trials in a quicker tempo. As for getting "stale," a variety of pieces is necessary to preserve the freshness of each one.
Regarding the pedal, I suggest that you use it judiciously from the very beginning of the study of a new piece; though never in finger exercises.
Watch Your Breathing
What is the purpose of associating breathing with piano playing, and to what extent should it be practised?
Breathing is as important in piano playing as in all physical exertion, and more so when we speak of pieces that entail the use of great muscular force; for this causes a quickening in the action of the heart; respiration naturally keeps step with it, and the result is often a forcible breathing through the mouth. Players resort to open-mouth breathing in such cases because they cannot help themselves. If, at the last spurt of a bicycle race, we should call to the wheelmen, "Breathe through the nose!" we could not wonder if our advice remains unheeded. This open-mouth breathing, however, need not be learned; it is the self-help of nature. I recommend breathing through the nose as long as possible. It is more wholesome than mouth-breathing, and it refreshes the head more. When physical exertion becomes too great then you will neither need nor heed my advice or anybody's; your nature will find its own line of least resistance.
Take a Month's Rest Every Year
Must I keep up my practice during my Christmas holidays of a month?
If you have worked well on your development during the spring, summer, and autumn it will be to your advantage to stop your practising entirely for a month. Such a pause renews your forces as well as the love for your work, and you will, upon resuming it, not only catch up quickly with what you may think to have missed, but you will also make a quick leap forward because the quality of your work will be better than it could be if you had persisted in it with a fatigued mind. In a tired condition of mind and body we are very apt not to notice the formation of bad habits, and since "to learn means to form correct habits of thinking and doing" we must beware of anything that might impair our watchfulness as to bad habits. The greatest persistence cannot turn a bad habit into a virtue.
[MARKS AND NOMENCLATURE]
The Metronome Markings