The difficulty of playing accurately and fast increases with the distance the fingers are lifted away from the strings, so never lift them higher than necessary; this rule applies to both hands.
Whatever the student's aspirations with the guitar may be, he must not neglect daily pratice of scale and arpeggio exercise. Begin each practice session by playing the chromatic scal. Then after the fingers become invigorated and free, practice lightly and fast; but not so fast that the fingers become tense, and evenness is sacrified.
Then practice various arpeggio formulas; (ex. p, i, m,a, m, i). Again the student is advised to play slowly and forcefully at first, the lightly and fast as the finger action becomes free. But make certain every note of the arpeggio is distinct and in even rythm; arpeggios should always "flow".
Now the fingers will be "warmed" to their task of playing and the student can much more beneficially apply himself to the problems of becoming a better musician and guitarist.