It is understood almost without the spoken word that in sports such as golf or tennis for example that there is an essential need to work on one's technique...often referred to as 'working on your game'..
It has been my observation for as long as I can remember that this could not be further than the truth with little exception in our sport. A major exception being with sprinters and hurdlers who very much work on their technique yet in looking at the distance runner it is regularly over looked.
Heck, in golf, they have a designated place to work on your game, it is called the driving range !
When I coach I use a small canvas on the track of 10-30 meters or so to evaluate and teach proper running technique and this is my 'driving range'. A controlled environment where through my verbal cues and physical demonstration I instruct in the science of proper running technique using my own style and original imagery and metaphors. I build a picture and a story from which my students can process and apply the information and message resulting in aspiration towards their own optimal functional movement and efficiency.
It is not enough to simply work on the 'motor' (cardiopulmonary) because no matter how refined you become in this area your motor will only take you as far as your running mechanics permit..at the onset of technical breakdown, cardiovascular performance will diminish. My advice is work on your technical efficiency in increments and when you are comfortable with your understanding and implementation of the specific increment then put it to the test under duress out 'on the golf course'... (road, track, trail etc)...have a family member, friend, training partner or coach take short video of you before and after a particular running element has been worked on, tried and tested. Immediate video diagnostic feedback is an excellent way to self evaluate and adjust to the task at hand and the agenda that you are trying to achieve within a given session.
Remember perfect practice makes perfect but first of all I say take a day to 'get off the golf course and hit the driving range'...Your 'game' will be all the better for it !