Don't change your form.
Getting professional instruction on running technique might seem like a good idea – improving your running economy is, after all, one of the surest ways to go faster for longer. Don't do it: Technique training for distance running simply doesn't work and can even be counterproductive. Research going back to the 1960s has shown that forced changes to form reduce running economy. Instead of tinkering with your stride, you simply need to run consistently, naturally developing a form that is most efficient for you.