Any tips to make your dog more excited and motivated in training sessions? She's sometimes really perky and excited, but other times she's kind of slow, it takes her a while to switch between tricks or she just looks generally less interested. I realise that there are just going to be times where she's not in the mood, but I want to increase her excitement and help her have more fun. I use high value treats, and often throw in a little session of tug for a reward here and there, too. Any other ideas?