All practice needs to be planned. This includes planning when to practise performing, when to develop new skills and when to solve problems. In general we need to practise a new skill until it is comfortable and familiar. In Nurtured By Love, p.42, Shinichi Suzuki says: "We simply have to train and educate our ability, that is to say to do the thing over and over again until it feels natural, simple and easy. That is the secret."
Two excellent compendiums of practice techniques are Simon Fischers Practice and Robert Gerles The Art of Practising the Violin.
Break difficult passages down into their various components and work on them one by one. Try an audit, for example, on Paganinis "Moto perpetuo". This could include:
Practise the sautillé on open strings at tempo with metronome. Is it reliable, even and clear? Does observing the musical shape and dynamics upset the control?
Improve the left hand by repeating four notes slurred at tempo. Repeat one bar several times (create a loop), monitoring tiredness and the ease and reliability of finger fall.
Practise slurred passages with separate bows and vice versa.
Practise on the wrong bow
Start a détaché passage on the opposite bow to normal (for instance, start up-bow on Kreutzers "Study No.8"), to work on evenness.
Practise backwards as well as forwards
Start with the last note and add notes or sections one by one. These mental gymnastics also help maintain focus in practice.
Try solving a problem by switching focus from one side to the other. This can have surprisingly quick results. For instance when confronted by a spasmodic vibrato action switch attention away from the left hand to the right hand, and work on ease of movement in the lower-half bowstroke. Any tightness in the right upper arm may actually be contributing to problematic vibrato action.
If the problem is shifting in arpeggios, try focusing on a bowing issue such as smooth string crossing.
We usually practise slowly to diagnose a problem and then to program the solution. However this is of limited use if we do not also practise with the relevant performance tempo in mind.
For fast passagework use a metronome and practise small units at half tempo to program, and then at tempo to check whether the programming has worked. Automatically increasing the speed of a metronome by one click every day can waste valuable practice time. See Gerle, The Art of Practising the Violin, pp.14-17.
Practising scales with a metronome and varying the number of notes per beat is also effective. See Sassmannshaus (www.violinmasterclass.com) for an excellent demonstration of such scale practice.
Practise difficult passages from memory to allow the mind to focus on the sound and physical patterns.
Insert rests, or leave out certain notes in order to focus on others. This gives time to diagnose problems and program solutions.
Practise on open strings
By practising passages on open strings we can analyse clearly what dynamic and what bow division we are actually using.
Play air violin
Practise movements away from the instrument. Bow in the air above the string, mime shifting actions with the left arm, or activate your passive upper arm movement for sautillé by cleaning your teeth.
Practise balancing the violin
Be aware of what holds the violin up and why. Practise without a shoulder rest or with your chin off the instrument or even both at once. Ysayes Exercises and Scales or Galamians scales in one position are ideal for this type of practice.
Listen to how you are playing not how you would like to play
The ear needs to distinguish between what our arms are doing and what we would like them to do. We need to direct the bow to play with spirit, or the left hand to vibrate with intensity, otherwise we will end up playing with a bland mezzoforte dynamic all the time.
You should take risks and make mistakes early in the preparation cycle for better understanding of the real needs of the piece. Don't leave performance practice and an awareness of overall shape and emotion for too long.
Resources - Bibliography
for www.violinmasterclass.com (Right hand, Détaché, Scales with rhythms)
Resources - Repertoire