Icewind Dale is more of a hack & slash type of game, so brute force will win the day. The more fighters the better. I'd recommend having two strong front line melee fighters, three characters to form the rear using ranged attacks, and then an extra more versitile character who can switch between range and melee as needed. All your melee fighters will want proficiency points in both swords or axes and also in a blunt type weapon to deal with all the undead your party will encounter. You will need a cleric, mage, and thief in your party, but in my opinion mages are not overly effective in IWD so you can settle for a multiclass if you wish. Thieves are flat out necessary with all the boobie traps, but since it doesnt take too long to max out the important thief skills you can also settle for a multiclass there as well. You don't even need 6 characters in your party for that matter, and a smaller party will gain levels faster. But you'll be less likely to be overwhelmed by swarms of monsters if you have more party members to occupy the monsters. As for race, dwarves make good tanks since they can have more hit points (19 con) and elves make good archers since they have +1 with bows and 19 dex. Gender is irrelevent, but try to have diversified alignments since there are a handful of alignment specific items in the game. But none of this really matters too much since you should be able to beat the game with just about any party combination. The important thing is to have fun... and go heavy on the fighters
