I could use some tips in training heeling and in motion exercises. My pup just turned 9 months old. I have been using a variation of Flink's ball on a string to build drive and focus. I prefer to use a two handled obedience tug because it allows me to also work on targeting bites at different heights and I can work the tug from both sides of the mouth. Also, I can do a little play fighting such as pulling the dog up to my side while he's biting the tug, or let him pull me as a way of giving him a sense of power and winning. I don't drop the tug on the release after he has focused, but rather, give the release and have the dog bite it and fight a little. My pup is coming into drive very well, showing good focus in the fuss position, has a good release and bites well with a good grip.
I want to move on toward more heeling and the in motion exercises. With the tug, if I move into heeling after the heel position my pup is somewhat hectic because he want to bite the tug. I have tried food, pretty much following Dildei's approach, and the food clearly allows me to position my pup better in the heel position, as well as helpling with a fast sit by moving the food quickly back to cue the sit. I can also reinforce the sit in motion best with food by taking a couple of steps past the dog when he sits and reaching out and giving him more food as he holds the sit.
I'd be interested in hearing others opinions and approaches when you move to working on more consistent and accurate heeling and the in motion exercises. Any potential downsides to using the food or the approach I'm using with the tug for building drive and focus?

You could practice alot of random sits and downs during drive building exercises.You could also practice "doodling" excercises wich are obedience exercises done in a small area instead of long drawn out heeling.Doodling exercises are like heeling one step and halt,2 steps halt, side step halt,step backwards halt,dog move to front from basic position,finish from front,sits and downs,also heel seeking. You can practice all these with out really going anywhere and concentrate on accuracy. When the dog is correct,release and reward.

I teach all my obedience with food.. I find I get much more accurate positioning..when the dog is understanding position.. I bring the toy back into play.