I once read a quote from a highly regarded martial artist which went something like, "There are people who claim to be masters and who are nothing, and there are people who claim to be nothing and who are masters." This is not an exact quote, and, I'm sorry, I've forgotten who to attribute it to. However, the idea behind the quote has influenced me quite a bit.
It seems to me, that with respect to running technique, this quote holds up well. A lot of people show up for session with me expecting to become an instant master, and they are usually very disappointed when they realize instant mastery is not a realistic expectation. Also, way too many people who have not mastered the skill end up over estimating their expertise and present themselves as something more than they really are.
When learning any skill, there are no shortcuts. You have to pay your dues and invest quite a bit of time into studying and practicing. It also helps if you can accept that there are people for whom the skill will come much more naturally. At any endeavor, there will be a wide range of abilities. A lucky few will be naturals, and an unlucky few will be hopeless, but most people will fall somewhere in the middle.
Remember, just because someone has mastered the skill, that does not mean they can teach it, very often they can't. The reverse is also true, just because some hasn't mastered the skill yet that does not mean that he or she can't help you on the way to mastery. Performance of skill and the ability to teach it are two different skills.