Run lightly on the feet, almost springy and as quiet as possible. Avoiding pounding or plodding.
Land on the midfoot or the balls of the feet. Avoid landing flat-footed, on the heels, or way up on the tiptoes.
Run with quick feet and practice having the feet pop off the ground.
Land with the foot and knee pointed in the same direction the body is traveling.
Lift the knees when running, bringing them up in front of the body. Avoid shuffling which results from running with straight legs and insufficient knee lift.
Choose a stride length that feels natural and comfortable. Ideally the feet should land directly beneath the hips or as close to it as possible. Avoid under-striding or taking short choppy steps, and avoid over-striding where the foot lands well in front of the body, sometimes resembling leaping and often causing runners to land on their heels.
Introduce and explore the leg movements of the running stride using fun challenges such as those in the Running Start Coaching Videos.
Remember that mastering these skills is not important at this age. The goal for kids is to explore movements, increase their body awareness, and begin to develop an understanding and capacity for efficient movement.