-Before you sell, enter the "Relations" screen and go by each Covenant. Ask if they want anything. If they want something, try selling it to them at double selling price or half the retail price. If they respond yellow, lower it by ones until it is green. Once done, sell everything else. Never buy potions, as they are nearly useless. Always use food.
-After defeating the final Boss, return to your hometown. When it is dark outside, go to the crystals outside your home. Turn the two orange crystals off, then turn the two red crystal on. Click the center blue crystal to open a secret passage which normally leads to four small gold chests. Collect all the items out of these chests. To collect them again, save the game and exit to the main screen. Click "Resume Last Game", then repeat the process until it is day.