Gosh tough question, but worth asking.
We are all different in our gait, because we all have different bone and muscle lengths and sizes which all affect biomechanics.
Usually the outside of the foot lands first and then the foot rolls in, and the arch sinks. Some people always land heel first, others keep their heels well above the ground when running.
One thing that I feel is very important is to get the feet to do a whiplash action before the foot leaves the ground, where the arch sinks just befor toe off and all of the bones in the foot move in a sequence which helps generate more force. You can practice this when walking too. When you do it walking, you get a more bouncy gait like a sprinter.
As we get older, or more tired, or when we have had some biomechanical problems, we lose this action and the gait becomes stiffer and less flexible, and the range of motion in the foot becomes less and less. If this happens to you, it is very important to reverse it consciously. It's definitely worth the effort. Look at different people walking. Some of them can't bend their ankles much beyond 90 degrees and so their stride gets shorter and shorter, weaker and weaker.