"Practise your finger taps. Notice how the 3rd finger is more difficult to lift than the other fingers. Practise your 1/3 and 2/4 in combination."
Practising technical challenges away from the instrument can be very useful. Here are some basic exercises you can do with the wrist resting on a flat surface.
Lift and drop the fingers with energy but notice that the fingers do not need to work too hard to get a good clear tap.
The 3rd finger is harder to lift as it does not have a separate tendon but is joined to the 4th finger tendon. So be sure to give the 3rd finger plenty of exercise.
Create your own finger exercises to challenge your coordination.
Resources - Bibliography
- for Indirect Procedures and Integrated Practice by Pedro de Alcantara
- and The String Play by Phyllis Young