Cloud Hands is one of the best containers for developing better rhythm and flow in your practice, but you've got to work on rhythm and flow separately. The reason is that you develop two very different qualities of mind when you work on these two seemingly related skills.
Better rhythm comes from "harmonizing" more and more moving parts over time in your practice. At first, we all face the challenge of not being able to feel into the body well. When you can't feel, you can't actually move different parts under conscious control (which is why I always recommend isolation work, like Z Health mobility drills). The more you can feel, the more connections you can make.
Ultimately, training rhythm isn't just about having more and more connections, though. It's about bringing them together in a coordinated way that doesn't take a lot of thought, or "harmonizing" all your moving parts.
Flow in qigong, tai chi, and ba gua is having a clear sense of what's moving through the body, not just how the body itself moves. At first, you need to build the physical container, then you begin to sense other, related movement, mainly fluids in this case, and then more subtle energy flows.
Ultimately, as the body feels saturated by fluids, the nerves feel flushed with chi, and the tissues feel permeable and heavy, you pay attention to the wave-like sensations going on inside the body, more than the external, mechanical movements of the arms and legs.
Cloud Hands is one of the best places to play with this balance of internal movement versus stable external shape.
In the April Practice Bonus, we go through the details of exactly how this is done.