The above is spot on... but the following general guidelines should help
A) ALWAYS keep the wrist of your fretting hand straight and NEVER grip the neck tightly.
(Imagine the tendons s-t-r-e-t-c-h-e-d accross your wrist joint when the wrist is bent - like string accross the corner of a brick, eeooou!

)
B) Don't press your palm flat against the bass neck.
You should have a loose claw like grip on the neck with your fingers relatively evenly spaced.
As a guide of how much pressure to use, you should be able to play without actually pressing your thumb on the back of the neck at all.
C) Use all four fingers on the fretting hand and keep them vertical where possible.
D) Keep your thumb level with your first or second fingers in every fetting position.
E) Don't use too much pressure on the plucking hand.
You can bend the wrist of the plucking hand on the basis that you shouldnt be plucking too hard.
This is the general rules I follow and I have no problems whatsoever since I rasied the height of my bass.
Check yourself agaisnt the above AND definitley get a teacher!!!