Right, this is the first time that I've played Baldur's Gate, as I missed it upon release and could never ever find reasonably priced copies of it afterwards. I've been playing for about ten hours now, my party is sitting at around level 2-3 and I've got the hang of the interface, the story is starting to develop a bit more, and so forth.
What I'm finding, though, is that combat is generally not a very enjoyable experience for me. It's not so much that the game is unplayable, as it is that it just feels cheap, unfair or totally random. Every single fight I get into, I feel could go one of two directions - either I mop the floor, or my party gets wiped and it's back to reload another save. I've built my party up as well as I've been able to considering how much I've played, but I'm just not sure if I'm missing something or not. It's like I'm totally at the mercy of the die rolls, and not in a good way. It doesn't seem like my skill really enters into the equation at all - I either destroy or get destroyed, and there's very little I can do about it except wait for those tasty critical hits. Compared to other RPG's I've played with real tactical depth, Baldur's Gate is frustrating.
I'm not sure if things improve later in the game, but given the number of pages in my mages' spell books, I'm assuming it will get a bit better. However, at these low levels the going is extremely rough and I'm not sure there's anything I can do about it except tough it out. Is there any advice anyone can give for combat, other than "spam potions, save often and hope for the best"?
A little preparation might help you from totally falling into the manipulating hand of "fate". I'm not sure where are you now, but if you find some combats to be difficult, try drinking some potions and casting some protection spells before them. And tactics is indeed important, as it's always easier to lure some enemies from the main group than dueling head-on.
I believe you also have a thief (Imoen?) in the party. She can stay in shadow and scout the battlefield before a combat, and can even backstab enemy spell casters if you are daring.
Your mage can still provide much help even at level 2-3. "Sleep" and "Charm" strong-muscle enemies and "Stinking cloud" is extremely useful.
And finally, remember that range weapon is the King of all BG games (except later in BG2 when your mage is powerful enough to fight on her own).
Good luck and enjoy BG, as it's one of the greatest RPG on earth.