Never sell or even pick up items that are low quality, cracked, etc. They give you less money and take up space. Only sell Enchanted bows because they cannot be repaired. Always repair items before selling to get more money. Armor in general gives you more money -- always pick up and sell it, especially Heavy Armor. Keep your inventory clean by having a row of potions along the bottom, a Tome of Identify and a Tome of Town Portal on the far left so they take up less space, and a key bunch. Keep as much space open as possible. You may feel very compelled to hoard potions, but it is more profitable to keep space open.