I worked out this exercise to help develop hand strength 
for hammer—ons and pull—offs which should provide a fluid
motion when using them, simply play each twice and move up
the fret board appropriately, it encorperates all 4 fingers
so you get a good work out :)



g—1—————————4—————————1—     —2—————————5—————————2—————
d———1h2h3h4———4p3p2p1———     ———2h3h4h5———5p4p3p2———————
a——————————————————————— X2  ——————————————————————————— X2 etc
e———————————————————————     ———————————————————————————

start out working on the top 2 strings and then move down a string

g———————————————————————     ———————————————————————————
d—1—————————4—————————1—     —2—————————5—————————2—————
a———1h2h3h4———4p3p2p1——— X2  ———2h3h4h5———5p4p3p2——————— X2 etc
e———————————————————————     ———————————————————————————

you'll notice it's getting harder, it should also encourage
a bigger reach, finally, move on to the bottom string, this 
is kinda tricky, but it should pay off with a stronger grip

g———————————————————————     ———————————————————————————
d———————————————————————     ———————————————————————————
a—1—————————4—————————1— X2  —2—————————5—————————2————— X2 etc
e———1h2h3h4———4p3p2p1———     ———2h3h4h5———5p4p3p2———————