I started a similar post to Jon's, but lunch got in the way...
There is a perverse joy in approaching a particular move, working on the ins and outs and finally achieving a proficiency that, while not the most practical thing in the world, does give one a warm, pink and fluffly feeling.
The problems, and frustrations, occour if the task is not properly laid out. To quote Mike Close's definition of how to play the piano - hit all the keys in the right order. When the more complicated moves are being discussed, it's vitally important to break the thing down into its constituent parts.
To take the Cascade as the current example; there are three or four things that are happening simultaneously. Now, it would be possible to say (albeit abridged) 'put your finger here and waterfall the cards'. When faced with instructions that combine several parts, as often happens in our field, it is at this point that we have to work out details for ourselves. These are the 'knacks' to which Jon refers.
With the Cascade, the move can be broken down quite easily. Without going into too much detail, you need to be able to waterfall the cards smoothly. Until you practice this on its own, the move will never work. Next, you need to understand the selection procedure, which again needs to be done in isolation. After that, you need to understand the mechanics of the control, again by itself. Once you can do these steps in isolation you can combine them; selection and get ready. When that has been established, selection, get ready and control. When you have that done you can start to assemble all the steps into the whole. Then you start working on the subleties and adapting the move to your hands.
The process is not neccessarily a swift one, but the results are stronger, and one has a better understanding of the move, which allows you to adapt and troubleshoot with more efficiency (this follows the four stages of learning - rote, understanding, application and correlation).
There's nothing wrong with working on the hard stuff alongside the basic moves, but your journey will me much easier if you break things down.
Take care, Ian