I didn't read all the responses. Heres my two cents. Best way to shorten the learning curve is to go to a fly fishing class. Even a one day class with classroom in the morning and some casting in the afternoon really is huge. Understanding the theory of how to make a cast is very important. My buddy and I started at the same time. I took the class he did not. I jumped right in and got pretty descent right away. He struggled for years and was always frustrated.
The class I went to taught everything from setting up your line ,different leader options, discussion on line and rod weights, flies, line management, casting retrieval and fighting fish large and smaller.
I wasn't a pro when I came out of the class but I had the knowledge of the fundamentals of fly fishing.