Icewind dale is tougher IMHO not as big & you only have one direction to follow, when I played the game monsters were not respawning so when you had weak characters trying to get more Experience Points to go up a level, it was hard fighting some tougher monsters,BG2 is better since it`s more open the gameplay gives you many directions to head of to.
Character wise,well I like a balance , 2 Warriors,Theft,cleric,mage, multi-class for last one,btw in BG2 ,you pick up your characters as you go along & can remove them if you find someone better.Read your journal in BG2 & don`t forget to talk to NPC characters for info & quest,& save often.
Great place for tips is the BG2 forum at interplay.com you have to join but it`s free & you can also access Icewind dale forum.
click here for BG2 site click on all baldur`s gate boards top left.