Brief Instructions on the Efficient Practice of the Slurs
1. The student should play legato exercises forte and piano, obliging his fingers to produce sounds of equal intensity. He may devise other formulas ascending and descending on each string.
Legatos based on scales are much more difficult. They should be played in all keys. After a ten-minute rest, the student will note greater strength and fluency in his fingers.
2. Chromatic octaves are excellent for achieving independence of the fingers of the left hand.
3. Scales are the basic exercises for developing speed and flexibility in both hands, and also for increasing the volume of sound. -- Andres Segovia