I'm not here today to talk to you about how to quickly fix your running form. I'd like to provide you some evidence that changes do happen over time, and you don't really need to think much about it.
I'm not a heavy runner. I'm not exactly tiny either. I'm just shy of 6ft in height and weigh about 157-161lbs, depending on where I am in my training. Until this year I've worn a motion control shoe (the NB 850/940 has been my go to trainer). This year I decided that I would try and make the transition to something with a little less motion control, something a little lighter.
So I purchased a pair of New Balance 860v2 and New Balance 880 and made those my go to training shoes with some lighter flatter shoes thrown in for my track workouts. It wasn't without a bit of pain that I've managed to get my feet accustomed to less control, but it took time and lots of preventative work. But there was no change in how I made my legs move. It was not a voluntary shift. Every time I tried to force my legs to move differently, my feet to land differently or my arms to swing differently I would find a new pain somewhere along the chain.
So I resigned myself to stop worrying so much about it. I changed my shoes and hoped that as I continued to run lots I would become more efficient. I had no idea if I had become more efficient or not until I looked at the soles of the most recent batch of shoes I've worn. I recommend you give them a look and see for yourself how my stride has changed over the last year.