Make sure you have a good grasp of the different key frame types.  For example, you may want to use smooth interpolation for the figure's legs, but linear interpolation to actually advance the figure's body.

My first attempts at animating were horrible experiences of trying to handle over/undershoot by adding extra keys and wondering why Poser was moving things in ways I had never told it to.  Learning when to use linear interpolation, and how to get a piece to hold still made all of the difference in the world.  Don't attempt anything this complex if you don't understand how different interpolation types will affect the same set of key-frames.