Great post and discussion. I'd dabbled in fly fishing for a while, and even had some good days out, before I got a tenkara rod last year. Since then I've spent mcuh, much more time fishing and had much, much more fun doing so. And caught a lot more fish.
My first rule to turn fly casting (been there!) into fly fishing is to fish where others don't. A little bushwacking and/or a few miles of hiking can make all the difference versus a roadside stream that gets lots of pressure.
The second rule is to know what the heck you're doing. Do some reading (the aforementioned books), do some research (some alpine lakes in my area have tons of fish, some are barren, it's good to know which is which and this is not always obvious), and get out there and find what works.
Third rule is to practice. You won't learn to cast in the wind until you cast in the wind, etc.
All that said, there are many exceptions to all of those rules. In the last few weeks I've had two excellent evenings of fishing which were yards from roads, and in areas I'd assume were well fished. On one occasion my stepdad and I caught ~50 trout in little over an hour, all within earshot of a major national park campground. The fish weren't being especially picky about the fly, either.
Last night I hiked up to an alpine lake and spent two hours catching fish ON AVERAGE every other cast. On one occasion I caught five fish in as many casts. I tried a bunch of flies for experimental purposes, and the only things which didn't work were big flies (most of the trout were small, and couldn't seem to eat a fly over size 14-16 (they did try)), and darker flies (fewer trout saw them). Everything that was lighter and well-hackled caught fish like crazy.
All of which is to say that fishing is fun, and fishing with tenkara is funerer.