Exercise her hard. No leisurely walks. When a dog is running, she has no time to duck her head and sniff the pretty flowers.

Of course, I always recommend spaying her. I think you OFA'd and CERF'd her, right? If not, then either spay or test her (I think you did...). Other than that, remember that a dog's nose is its strong point. When Happy goes on a walk, she uses her nose to "discover" the place in the same way we take in sights with our eyes. Because of this, I never rush Lucky because he sets his own pace. If he wants to mark, then that's fine with me. I won't get angry because he's answering "nature's call"