Charisma affects your appearance. Shopkeepers are more likely to give you better deals if your charisma is high. Constitution gives you additional health and enables you to drink more. Dexterity helps you hit more often and evade attacks better. Intelligence provides you with additional spell points. It also improves your ability with certain spells or skills. Strength enables you to hit harder and carry more. Wisdom, although it gives no spell points, enables you to perform certain spells and skills better.