Never
Fail to maintain a correct position at piano.
Wrap your feet around the piano stool.
Lay hands on keyboard in a careless manner.
Fail to keep the hands in correct position.
Fail to relax shoulder, arm and hand muscles.
Omit phasing, musical terms and marks.
Fail to place accents on proper beats.
Overlook key and time signature.
Fail to count loudly and evenly.
Play heavily, always lightly and gracefully.
Play in a careless manner.
Imitate; always be original.
Forget, fast practice means FAILURE.
Forget, slow practice, sure road to SUCCESS.
Study and practice without the MIND directing".
Fail to get the spirit of a composition or a study.
Forget that theory and practice go together.
Forget conscientious study and practice makes thorough musicians.
Forget without these essentials there is no MUSIC.