Set your game to "Autopause on Enemy Sighted" in the options to ensure you aren't ambushed.
Maximize your primary combat stat (Strength for melee, Dexterity for ranged) and Constitution (16 is the "soft cap" for most classes, though Fighters benefit up to 18+). Baldur's Gate Enhanced Edition
You can reach a maximum of 161,000 XP in the base campaign. Combat & Survival Tactics Set your game to "Autopause on Enemy Sighted"
Aim to have at least five party members equipped with ranged weapons. Ranged attacks can often end battles before enemies even reach your front line. Baldur's Gate Enhanced Edition