Choose a number of notes between 1 and 8 and play it evenly to a metronome on each string in the following order:
#1 E A D G B e B G D A
#2 E D B e G A
#3 E D A G D B G e G B D G A D E A
For example, if I had picked the number 5 and exercise #1, I would play 5 notes on the E string, 5 notes on the A string, 5 notes on the D string and so on.
Playing with a Pick
When using a pick it is important to alternate direction (down, up) when repeating notes on the same string. The most economical way to pick 2 notes on exercise #1 would be to play Down Up on the E A D G B and e strings and then Up Down on the B G D A and E strings if you were to repeat the pattern, which I recommend you do. The pattern will be similar with other even numbers (2, 4, 6, 8). When picking uneven numbers, such as 3 notes per string, the pattern would begin Down Up Down on the E A D G B and e strings and then become Up Down Up on the B G D A and E strings. The pattern would also be similar with other uneven numbers (3, 5, 7).
Notice that when exercise #1 descends (i.e. E A D G B e) each string begins with a down stroke and when it ascends (i.e. e B G D A E) each string begins with an up stroke. This will continue for exercise #2; however now there is string skipping involved. For exercise #3 the pattern is still the same but the direction now changes constantly. If you were to play exercise #3 with 2 notes per string the pattern would begin Down Up on the E and D strings, then Up Down on the A string, then Down Up on the G string, then Up Down on the D string, etc.
The motion with which you would start for any exercise would be dictated by the direction you are going. If you are going to a string above the one you just played (i.e. B string to G string) you would begin with an Up stroke. If you are going to a string below the one you just played (i.e. G string to B string) you would begin with a Down stroke.