-Save the game, mess around with your equipment on what it does, how you can use it, and how it works best. For example, always load up on items commonly used but save 2000 to 3000 for the odd item.
-Puddles dry up immediately after an NPC reacts to it. Either use more than one bottle or get a group to enter the puddle together. Holy Water may stop one undead from passing through, but the second can get by after puddle dries up from first undead. Aim carefully; hitting an undead with Holy Water directly will hurt it, but having the puddle under it will finish it off.
-Water Arrows hitting an outer edge of a Moss Arrow carpet will spread the carpet a lot farther. Moss Arrow at someone's mouth will keep them busy choking long enough to slip by without attracting attention or wasting Flash Bombs.
-Save before you sneak around Hammer or Pagan sites. If you can move around without being seen or detected, you can steal items without getting penalized. Otherwise if you are running haphazardly, they will know that you took it and you will lose faction status.
-Avoid being seen around any corpses or puddles of blood. Even if an NPC killed the body, you will still be blamed and hunted down for it.
-The docks is a good place to make bodies disappear in water, although this will kill unconscious bodies.