This is what I did when decided to farm the last pieces I was missing.
- Went Pure Black Character Tendency (doesn't affect drop rate, but I was Black when I decided to farm).
- Went Pure Black World Tendency (Black World Tendency increases enemy damage and souls earned, and yields better item drops, most especially for Ore).
- Held Large Sword Of Searching in my Off-Hand while killing the mobs that droped my items.
Here's more information on the Large Sword Of Searching from the Demon's Souls Wiki.
At some point, something must have come from nothing...
...nothing can come from nothing...