When playing trills make sure that the lower finger contacts the string firnly enough and the trilling finger lifts to a consistent height.
Lift the finger up high at quarter tempo. Although the finger does not lift as high at tempo it must retain the energy of lift needed for clarity.
Look for the optimal hand balance to support the trilling fingers. In this clip since the 3rd and 4th fingers are not used, the hand is centred around the 1st and 2nd fingers.
Practising in three tempos one after the other is useful so that we can immediately check that the action we have programmed at quarter tempo works at tempo.
Slow practice is good for diagnosis and programming. Fast practice is good for checking that the new skill works for patterning (thinking in large units) and for preparing for performance.
To warm up the left hand practise elements of the basic skills needed for your current repertoire (likely to include finger action, shifting, finger independence as well as scale and double-stop routines).
Here the lizard tongue exercise focuses our attention not only on the basic fingerfall action but also warms up our ears so that we demand optimal clarity of the articulation of each finger.
Practice breaks or pauses give us thinking and planning time in the middle of phrases so we can solve technical issues.
In this excerpt from Kreutzer “Study 22”, Fintan pauses on the lower note of the trill to allow the left hand to prepare for the next three notes.
It’s important to keep sounding out the note with the pause by keeping the bow moving. This lets us hear that the trill has stopped.