What we did with Woolf to begin with on walking, is when he began to pull or fall behind is make a quick 90 degree turn. He learned he had to keep his eye on us. Some on here have used the stop and start method and it worked, the pup starts pulling, you stop, have him sit beside you then begin walking again.
For heel, look up Micheal Ellis on youtube or on leerburg.com. Search for his 'Focused Heeling'. The full DVD is very good, it can be rented through BowWowFlix, though I think there is a backlog on their copies of it.