Why is it called rise and fall? It should be called "Fall and Rise"! When you try to add rise and fall to smooth dances, like the Waltz or Foxtrot, you need to remember that it's the difference in your height that makes it appear so elegant.
What I mean is, without any "falling" the rise doesn't look as dramatic, and vice-versa.
If you begin with your knees locked and straight, and then try to rise up to your toes, the effect will not be as impressive as if you begin with your knees slightly bent (or soft), lower slightly, and then rise up on your toes.
So how do we apply this? Well, in Waltz we'll begin with our knees soft, and lower on the "1". The rise to the toes begins after this, but we need to be careful not rise fully until "3". "2" can be considered a transitional step. There should still be some room for extension up to your toes by the time you get to "3".
Next, lower as you step on the "and 1", returning to your original start position by the "1" has arrived.