A good pull is like having an 8th defender on the field. The goal is to get the disc as far down the field with as much hang time as possible, to give the pulling team time to run down the field, and get the receiving time starting off as far away from their end-zone as possible.
This video, posted with permission by Colin McIntyre, discusses how to get more distance on a backhand.
Note 2: Some people struggle bringing the disc back against their forearm. I grip the disc with my off hand when I do this. But the alignment is the important part of this; not the actual disc-to-forearm contact.