kmonster: Play a sorcerer. Arcane magic is overpowered in the game, sorcerers are most powerful, unavailable as NPCs and can cast spells spontaneously without the "know before resting which spells you're going to cast next day" metagaming nonsense.
Just create a sorcerer with 18 str (for carrying capacity ), 18 (19 if elf) dex for AC and ranged attack bonus, 16-18 con for HP, 9+ int for using scrolls, 3 wisdom since it's useless and 18 cha for better quest rewards.
Arcane magic may be overpowered, but not until mid levels, and playing a mage PC would probably be overwhelming for a beginner, not to mention one single lucky hit is enough to kill you.
Also, I don't really like sorcs in BG 1&2, because imo, there are more useful spells at each level than they are allowed to learn, especially for levels 4, 5 and 6.
And frankly, if you want an overpowered char, starting as a human fighter with at least 17 int and 15 strength, then dual-classing him to wizard around lvl 9 makes for a more powerful character than a sorcerer.
On-topic:
My suggestion would be to designate a tank (a fighter PC with 18 dex and con works best, but Minsc or Kivan or Coran can do fine too), give him the best armor you can buy and let him attract all the enemies by positioning him far in front.
Equip all your other characters with bows, or slings if they can't use bows, then shoot down all the enemies.
For enemies which are too hard to tank at low levels (ogres and such), just make the tank run around so they can't hit him and keep shooting them.
Your main advantages before you get more levels and magical equipment are the stupid AI of enemies and the fact that your characters move faster than most enemies, so use that.