#1
Hey, when I'm practicing I usually find my hands getting tired and sometimes cramping. Anyone suggest any exercises or stretches to perform before playing to prevent this?
#2
I know you are probably like... I hope no one says this, its no help, but you have to keep practicing to build this up. Try learning "Message In A Bottle" by The Police. That has pretty big stretches. Also try to learn and practice this part of Eruption:

E---------------------------------------------------------------------------|
B---------------------------------------------------------------------------|
G--4h5h7p5p4---4h5h7p5p4---4h5h7p5p4---4h5h7p5p4------|
D-----------------7----------------7---------------7----------------7----|
A---------------------------------------------------------------------------|
E---------------------------------------------------------------------------|


Keep doing that over and over. That will build strength and endurance and somewhat, reach. Also doing bends with your pinky, backed up with your other fingers, helps a lot. At first it will be very hard, but you will eventually get it.
#3
Get 2 soft foam tennis balls and squeeze them when watching TV and this'll help build up endurance when you don't have the chance to play. Then move on to rubber balls once you feel you're ready.
#4
Try this starting on the high "E" string:

E--0-2-1-3-2-4-3-2-------------------------------------------------------------------------------------

Try that same progression ascending to the 12th fret, moving a half step to each fret. Once you finish ascending, try decending. Once you finish the high E string, try it on the rest of the strings.
#5
Quote by AgentOfFortune
Hey, when I'm practicing I usually find my hands getting tired and sometimes cramping. Anyone suggest any exercises or stretches to perform before playing to prevent this?


Without actually seeing what you're doing, I'd say getting cramps and tired hands
is more a matter of way too much excessive tension when playing. All the
warmups in the world won't fix that. Sure you need muscle strength and flexibility,
but it's much much less important than skill & accuracy. Because with the latter
EVERYTHING takes much less effort.