Gus used to pull really badly, so we got him a harness and he is fab in it!
Plus he looks very smart in it!!
I have also tried the stop every time they pull method, where you stop and make the dog sit every time they pull wait for 5 seconds and start off again. For the first few days it seems like you aren't getting anywhere as it's stop, start, stop,start, but when they realise that they don't get where they want to go any quicker by pulling they soon give up!