Walking your dog is good, but in my experience they need more than walks. Play, fetch, use a flirt pole, or spend time training. Mental work tires them out a lot. I also like to give my pup some off leash free play time each day...but I get that that can be a difficult thing depending on your circumstances. If you're walking her and training her while at home, that should be good enough to meet her basic needs...but if you can get her out occasionally for an adventure now and again that would be awesome too!
It's not the size of the dog in the fight, it's the size of the fight in the dog. Mark Twain