When your magicuser(s) has got the spell "fireball" 
and your priest(s) has the spell Fire res, then 
put fire ress on your fighters whitch should be in
the front of the party (the spell fire res lasts wery
long so u can do this when u wake up). When you 
encounter monster send your fighters against the 
enemy and let the rest of the party stay. Now the 
fighters with fire ress should be alone in front 
whith the mosters then blast away with fireball 
towards the monsters(the fighters whith fire ress 
will only take 1-2 in damage from the fireball spell 
(this has saved me in a lot of nasty situ..).