At each stage of the learning process and for each swimming skill you teach, devote some time specifically to feeling the water and its interaction with the body. When he’s learned to put his head underwater, to do the streamline position, and to kick, have your child experiment and explore.
What happens if you push off from the side with your arms or legs? What happens if you move your arms backwards? Forwards? Up or down? This experimentation is critical, because these things are all different than they are on dry land. Moving your arms backwards propels you forward in the water. Moving your arms down propels you up. Starting to understand this will give your child confidence and control in the water.
Have your child solve problems. How can you go backwards in the water? How can you go forward? Which movements and positions move you with the least effort? Which movements and positions move you with the least splash? Help your child learn to push back to go forward and down to go up.
Use play. Practice moving through the water like a fish or a ninja, disturbing the water as little as possible. How big a splash can you make for fun? How do you do it? Practice sitting on the steps and hitting the water with the flat, broad parts of your body. Okay, now how small a splash can you make? Can you slice your hand into the water without seeing any ripples at all? Practice no-ripple swimming. You’re learning to sneak up on Mom or Dad in the water, so that you can pounce on them.
Kids will discover these things on their own by playing in the water, but you can speed up the process by specifically guiding your child.