Running faster, more efficiently, and injury free is what runners strive for, and having good running form is paramount to achieving these goals.
The simplest and easiest way I have found to find your perfect form and rhythm specific to you is to start slow and build. To start, the quickest way to adjust your technique is too utilize a treadmill. Starting at a slow walk, slowly increase the speed, noticing how your stride length gradually becomes longer as you increase your speed until you eventually break into a run while maintaining that long reaching stride.
This long reaching stride that forms out of your natural walking stride is what creates the heel strike and the unwanted impact forces that create the injuries that we sometimes succumb to with increased training. A good running stride is more similar to biking than walking and to create your natural cycling stroke reduce the speed of the treadmill to the original walking speed and at this slow walking speed break into a run forcing your natural hip switch and hamstring activation whereby you are essentially lifting your heel to your hamstring eliminating your low walking style leg swing. As this stroke pattern starts to feel natural and rhythmic slowly increase the speed of the treadmill until you settle into your normal training pace.
With this in mind start each run either on treadmill or outdoors by walking slowly, breaking into your running stride at the same speed and then ever so gradually increase your running speed with the same hip switch.
A key area of focus for force production is the speed at which the thighs are switched- as one thigh flexes into the swing phase, the other extends into the stance phase. This switching action is a key focus in cueing and enables maximum efficiency with the focus on extension and not flection with an erect truck and stable spine position.
Your foot should be prepared to land (system stiffness) and your cue to switching is the landing of your forefoot as your heel settles back and touches ground to allow for proper loading and vertical impulse. While foot contact is occurring there is what is called an extension reflex or switching in the air with the power coming from the hips and not from pushing with your toes. The hip should be thought to work in a piston like fashion. Once the hip is extended, the foot will come off the ground and the recovery cycle will begin.
The lower leg will lift off the ground and fold so that it comes close to your buttocks (how close depends on the speed you are running) then pass under your hips with the knee leading. Once the knee has led through, the lower leg will unfold and land close to the center of your body and directly underneath the knee.