“Remember, in conducting, that your thought and gestures will almost certainly be too late rather than too early. Anticipate everything.
“When actually conducting never think of technique; it is loo late by that time. It is your job to impress what you want on the orchestra and choir somehow. How you do it is a matter for consideration afterwards, or better still, beforehand.”
“A great many qualities are needed to conduct rehearsals successfully. The two most important things are to see that everybody is happy and comfortable and to waste no time. Never stop the orchestra to say what you can show with a gesture. If a passage is going very badly, persevere with it to the end of the section, then point out all the mistakes and take it right through again if there is time. Continual stoppages irritate everybody and waste a great deal of time.”
“An enormous amount of time in rehearsing can be saved by preparation of the copies, and here the conductor must never spare his own time in seeing that the parts, if in manuscript, are clear and their expression marks uniform, that the lettering is consistent and that the letters are in places where they will be wanted for rehearsal. Everything possible should be marked in the parts beforehand. It is almost always the conductor’s fault if he has to ask the orchestra to mark anything at a rehearsal, unless he has unlimited time for this.”
(From “A Handbook on the Technique of Conducting”
by Adrian C. Boult.)