When creating characters, one thing I always do is take every point off luck and put it all on endurance so that all my characters have max endurance. The remaining points go on my cleric's personality.With regard spells, make sure you have at least ALL healing spells plus:-
Sparks
Starburst
Town Portal
Lloyds Beacon
Water Walk
Fly
Jump
When you've learned Dark and Light Magic, get Day Of Protection, Day Of The Gods and Hour Of Power plus Shrapmetal for quick kills.
I may have missed some, but it's a start. There are plenty of other useful spells, but these IMO are the most essential.
Once I've collected enough herbs, I create a potion of endurance and a potion of accuracy for all characters. If you do NWC, don't do the Shrine first. Run into NWC and there is a box in the bosses office that casts DOTG on your characters. Do that and heal up to your new level before doing the shrine and save the game before you leave NWC to do the shrine as you might still die. Hope this helps. 