The old favourite is to do 5 different excercises...
First off use just your index, second and third finger and choose say the 3rd, 4th and 5th fret of every string. Using an up-down-up pick stroke, go from 6th thru to 1st string...then without stopping go backwards from 1st to 6th. When you get back to the G on the 6th string, go up to the G# (4th fret) and do the same on the 4th, 5th and 6th fret.
Once you've done this up til it starts to hurt (!), change and NOW open up the excercise to your index, 3rd and 4th fingers on say the 3rd, 5th and 6th fret of each string, AGAIN, work up the neck until it aches.
Next would be similar but change the fingers and frets to index, 2nd and 4th on the 3rd, 4th and 6th fret upwards.
The two final ones are the hardest. All four fingers in a 3rd, 4th, 5th, 6th line and then open it up to the 3rd, 5th and 7th frets-with this one you'll have to stretch but try not to move your hand too much (it looks like a knitting machine going for it when you get going!).
Start all these on something like 90BPM with a drum program or metronome and work your way up speed wise as you start to improve. Headphones maybe required as it's totally NON-musical!