To add, I'm not sure how you do your training sessions but it helped a lot if I did about 5 minutes one day, 10 minutes the next, and then another 5 minutes the next. Also, finding something that REALLY motivates her is key.
It's different for every dog. For Kiara, it's tennis balls or just for me. For Simba, it's cheese. For Nala it's anything food related!

I usually put the other dogs away and wait until everyone is either asleep or gone. They seem to concentrate more on me and what i'm saying with no one else around. Then once they get the hang of it they do it with others around.