There is an interesting thread running on the ABRSM Forum with the title How to Practice Better
Here are my thoughts …
You cannot practice effectively if you are tired, ill, malnourished, or generally run-down, so make sure you are:
– getting enough sleep on a regular basis
– eating sensibly
– getting some non-injurious aerobic exercise every couple of days
RELAXATION and BREATHING
Try a bit of Yoga or Tai Chi to learn to breathe properly, and to avoid unnecessary tension.
Many musicians (e.g. Yehudi Menuhin) have used Yoga, but I think Tai-Chi is more suitable for those of us brought up in Northern climes who have not maintained the flexibility to sit cross legged in the lotus pose. Alternatively, treat yourself to a few Alexander Lessons.
Study your pieces away from the instrument before playing them for real. Aim to imagine the sound as realistically as possible, then imagine the sensations of actually playing them as well.
Set definite times for practice and stick to them, even if you don’t feel like it. [Unless the reason you don’t feel like it is because you are tired or ill] … this does not stop you from doing extra, unscheduled practice if you like.
Turn off your mobile. make it clear to others in the household that you are not to be disturbed except in dire emergency [e.g. house on fire, imminent arrival of tsunami, house in path of nearby tornado …]
KNOW WHAT YOU ARE AIMING FOR
Have a few clear objectives in mind for each practice session, and know
– what you need to do to achieve them
– how you will know when you have achieved them
When your concentration begins to flag take a short break before continuing
HAVE A GOOD BALANCE OF ACTIVITIES
Aim each day to do some :
– work aimed at overcoming technical problems (may be etudes, exercises, or parts of pieces)
– memorization of new material
– sight-reading (both as sight reading practice and to explore new repertoire)
– revision of pieces already learned
and if they interest you, you might also want to improvise a little and/or work out some new piece of music ‘by ear’.
EVALUATE YOUR PROGRESS
From time to time, record yourself so as to really hear the sounds you are making. [But not too often as it can be discouraging, and also you need to learn to hear accurately while you are actually playing]
TWO STEPS FORWARD, ONE STEP BACKWARDS
This is just the way it is, you may master something, only to find that a day or so later you have slipped back .. but not all the way. It can take several learnings before something sticks for good.
You may not see any great progress during a session. Often it is the next day, or a few days later that improvement becomes visible. So if you have got something right (however slowly you had to play it to get it right) then just repeat it half a dozen times (with full concentration, and total accuracy!) and move on.