Has anyone found success through Don Sullivan's dog training secrets?

I just recently got my package in the mail and was very pleased to find it all there. I have watched the DVDs twice already and have begun the no pulling and sit and down and stay commands. Has anyone been having trouble with the heel command? My dog really tries to resist me when I do this one and does not want to keep his head up. I hold him up with the leash and collar on, but he still wants to sulk and keep his head low to the ground. I have tried to hold his head up with my free hand while leading him with my other and keeping him close. He also does not want to stay very close where he is supposed to. He wants to tug and shy away like I'm going to kick him or something. He does have a history of abuse comingfrom an area where dogs were plenty and roamed free and not really cared for by humans. He is being obedient to me and my friend and gets lots of love and attention from us. I'm just wondering if anyone has had the trouble of their dog resisting or being scared of the heel command when they walk.