1.To keep practicing what one already knows.
2.To play a piece from beginning to end several times (with mistakes) instead of stopping and dealing with the mistakes once and forever.
3.To work without a short/medium/long term plan. Or in other words: to jump form piece to piece without ever perfecting any. Working in such a way that the daily work does not add to anything at the end of a week/month/year.
4.To practice without a clear and specific aim for every practice session.
5.To practice mechanically (which often means unintelligently), that is, no thought is given to the possibility that the practice strategy being used may be unsuitable for the problem.
6.To practice by time rather than for results.
7.To constantly rush through pieces at top speed.
8.To try to tackle pieces that are too difficult. To try to tackle sections of a piece that are too large for a practice session. To try to learn a whole piece in ten minutes.
9.To stop practicing the moment you get it right. (it is when you get it right that you should start practicing!)
10.To practice mechanically without focus, concentration or mindfulness.
11.To keep changing fingerings.
12.Always starting to learn a piece from the beginning, and then never finishing it.
13.Avoiding the difficult bits of a piece and leaving them to learn/practice last.
14.Practicing a piece in section but not overlapping them, so that when the time comes to join the bits, there is an inbuilt hesitation at the seams.
15.Playing only by memory.
16.Playing only by reading the music.
17.Playing only by ear.
20.Angling the hand to help the thumb reach the keys (this puts pressure on the carpal tunnel on the outside of the wrist, and may eventually cause carpal tunnel syndrome).
21.Misaligning the joints from the shoulder girdle down to the nail joint.
22.Breaking the nail joint (either way)
23.Using the heels of the hands to support the weight of the body on the piano (this is usually caused by having the feet tucked under the bench – another very bad habit)