The best way to learn is get a cheap rig and just go out and fish with it. You’ll make some mistakes but you’ll get tired hang of it in no time. The key is the rhythm (picture having about ten foot of rooe you’re needing to flick over your shoulder and back … kind of like a whip but much gentler … you don’t want it to “crack” like a whip (it will tangle up in the leader and tippet) but the rhythm is similar. As long as they don’t get spooked, the fish don’t care much about how cool you look while casting, which is fortunate for me … I’m sure I look like a car wreck in slow motion when I cast but I still enjoy it!
I just bought my first fly rod/reel. I'm going to fish the yellowstone and Missouri rivers in a couple weeks. One of my bucket list items. It's not as hard as I thought but that's probably because I'm doing it wrong and don't know it.
Good on ya! I haven’t been fly fishing in decades, not since I lived in Wa State and fished for salmon, steelhead and dollys. Been thinking about blowing the dust off my 9’ 5 weight Sage but knowing those are out there I may want to rethink that plan. 
