Baldur's Gate II is my favorite game, doesn't mean i'm good at it though. Here are some very simple BGII questions, hopefully you guys can help since most of the online guides I read don't help that much. You don't even have to actually answer the questions, all you have to do is point me in the direction of a good guide that actually helps.

How do you defeat dragons in BGII? I've come up against them but I never fight them, I tried fighting Firkraag with the dragon stuff but I got munched, I did get up to Suldanessalar but I couldn't talk my way out of fighting the dragon so I started a new game.

Is there any way to stop Yoshimo from betraying you? I think I've tried all of the dialogue options but it doesn't work but in a guide I read it says you can stop him betraying you.

Who do think makes a good party? Currently I have Me, a Wizard Slayer who is actually quite useless at slaying wizards, Minsc(Ranger), Jaheira(Fighter/Druid), Mazzy(Fighter), Aerie(Mage/Cleric) and Imoen(Thief/Mage). This is just after being betrayed by Yoshimo, I haven't got up to killing him yet though.

Is it worth skipping the Underwater City and going straight to the Underdark? I did this in my last game but apparently there's some good items there.

When I get to the Underdark, is there a way to shut off the elemental portals that are right next to the entrance?

One more thing, could someone please tell me where some artifact pieces are? All I have now is Pommel Jewel of The Equalizer and Gesen Shaft and string.

This is it, I think, and the only real Vital Question here is the dragon one, If I can beat those I could probably finish the rest of the game myself.