For years, many coaches and athletes have focused on trying to match a certain so-called ideal running form. The problem is that nobody knows what this "ideal" form is. There is an optimal form for any given person. However, because our skeletal structure, body dimensions, insertion and origin points of muscles, and distribution of mass are all unique, the best form for one person should not match that of another person. That is part of the reason we see different foot strikes, postures, stride lengths, and so on between runners.
Runners that are convinced of the importance of changing the way they run often do more harm than good. Leaving their movements the way their bodies naturally prefer, but making those movements consistently the same with every step may be the best choice. Since the 1990s, research articles have shown smaller variability in stride characteristics among runners that are more economical (see the references found below). When the variability of stride length, stride rate, time on the ground, and certain joint angles increases, the energy cost of running also increases. Those who run with very consistent movements are more economical.
As you browse running magazines, the Internet, books, and journal articles, you will find evidence that midfoot striking is better than heel striking, a shorter stride is better than a longer one, and less time on the ground is better than more. You will also find evidence exactly opposite to those characteristics just listed. The full answer must be out there, but applying the findings of one article or blog post assuming it will work for everyone is very risky in terms of injury and will likely impair performance.
There may still be times when a change in running technique is appropriate. However, most people will find greater improvements through practicing the technique that their body naturally goes toward, thus reducing the variability of their steps.