I'd hold the ball cupped in your left hand then reward by holding the ball right above her head and letting her jump straight up to bite. Then tug. Then if you want you can fetch out of that. If you're going to throw I'd throw to the side. Throwing forward has no benefit especially when the main problem with attention heeling is the forging. I also sometimes hold in my right hand and reward behind me. Keeps the dog from forging if the reward is never going forward.
Imo the more the dog looks towards your left side the better. Even if you teach to look you in the eyes, during a routine you are looking straight forward and some dogs can wrap around a little to try to look you in the eyes. Imo the left arm pit is the perfect spot for the dog to look.