[F. Gottwald]

i don´t have tob, so not sure if these work through the whole game...

keep stonekins up at all times. if you´re having problems, also keep long-duration summons like skeleton warriors with you.

take enemy casters down quickly, before they get their protections up. if you aren´t fast enough, pay attention to what they did and , consecutively, what their vulnerabilities are - debuffing spells are usually not the most efficient way to get rid of them - area spells, weapons with elemental damage, normal weapons, insect spells... often one of these works.

get hidden people into positions before you start a frontal assault... this is most obvious for thieves, but having that ranger where you need him when the fight starts can be a sizable advantage as well.

some fine and not too smelly cheese:

cloak of mirroring, cloak of reflection, lots of lightning bolts (best from sequencers): have two characters on opposite ends of a big meanie like your average dragon and give him the shock of his life.

send a jellyfied (and probably stoneskinned) character into the fray to attract their attention and dump numerous death fogs or similar magic on top of him (alternatively, get someones fire reistance to 100 or above, have him take on things singlehandedly and dump a few fireballs/meteor swarms etc on top of him or use spell immunity instead of polymorph self - these have the advantage of not impairing the bait chars fighting abiltiy but they remain vulnerable to enemy magic.)

make soemone invulnerable with multiple armours of faith... if he can´t cut down all the opposition until the protection wears off, throw in an improved haste.

extremely mature and smelly cheese:

cloudkills from afar (preferably from a wand - ignores mr)

blade barrier and sanctuary: most people will allow themselves to be cut into ickle little bits without doing anything about it.

whack them, turn invisible before they hit back: staff of magi allows you to do that as often as you want. obviously, this works best with thief/mages.

make full use of projected images/simulacra: have them summon lots of things like skeleton warriors or have them use up priceless charged items... like protection from magic scrolls or, best of all, that rift device your familiar carried out of hte sewers for you...