Last night I farmed to get the Normal Staff of Herding Pattern to drop from Izual. Got sick of having to run from the start of the Prime Evil quest every time I killed him so decided to try and use the Checkpoint Strategy with another person.
So you need 2 people for this. Clear to the Entrance of The Great Span on the Silver Spire Level 1. Once you both have the checkpoint, have Player B Leave game.(player A will be the one farming the pattern).
Player A enters and goes on to Kill Izual, Player B resumes game.
As soon as Player A Kills Izual, if the pattern doesn't drop, just join player B's game instantly from menu and you'll be at the Great Span checkpoint again.
Go Kill Izual again. Should take around a minute per kill.
Saves time starting a new game, and running through the Silver Spire looking for the entrance to The Great Span.