Let's say we have a velocity study of 8 measures in 4/4 time of 16th notes. Take each group of 8 notes as a section or segment. Play the first 8 notes 5 times in a row, if you make a mistake or miss a note you must start again with time number one. Than do the same with segment number two, five times. Than play from the beginning to that point once. If you make a mistake you must start again. Than we play segment three five times in a row. And from the beginning to that point once, and so on until we get to the top. Remember to use all models; single tongue, "K" tongue, Double tongue, Slur 2, Slur 4, Slur all (in one breath).
Repetition is the mother of perfection.