One tip that helped me greatly in my first playthrough is to purchase the Bow skill for everyone in your party, and likewise buy bows/crossbows for everyone. Then you can mash spacebar in real-time combat while the enemy is still far away and kill the weaker ones or severely damage stronger ones before they get into melee range. The level 1 bow skill becomes obsolete after lvl 10 or so, but by then your characters will have developed their class skills enough to cause real damage. Just employ the kiting tactic when fighting enemies out in the open or in dungeons: keep backing up while mashing spacebar and pelting enemies with arrows. The good thing is that you can never run out of arrows.
Go with the standard party: human knight, orc thief, dwarven cleric and elven sorcerer. They cover all the skills you'll need. Let your sorcerer focus on fire spells at first, as they cause the most damage. Later you'll want to develop the water element to get the most useful utility spells. I also recommend putting points in your cleric's Merchant skills as this will net you large amounts of gold when selling excess equipment. Alchemy is also nice, but you needn't go beyond Expert.
Those are the main tips I can remember off the top of my head. If I remember any more, I'll post them here.