Ganomee

I am having trouble getting my dog to ignore people and other dogs when we walk by them. Out of all the training I've gone through with her, loose leash walking has been the most difficult. She finally seems to have gotten the hang of it, until she sees another dog or a person approaching. Then she loses all sense of what she's been trained to do, and pulls and jumps to try to get them to play with her. She is well trained when I say "leave it" as long as it's an inanimate object on the ground, but if it's a person or animal, "leave it" doesn't work. I have tried touching her on the neck to get her attention back to me, and it works while we are still some distance away, but as soon as we are close to the person or animal she ignores me. I have tried redirecting her attention to a treat in my hand, but that also only works while the distraction is still some distance away, and then she ignores the treat. Does anyone have other tips for me to try?