You might be interested in Peak, by Anders Ericson. The author mentions him briefly, but the book is well worth reading. He looks at the case of Benjamin Franklin, and some of the strategies he used. In brief, he found pieces of writing that he especially admired, and transformed them in various ways, then tried to reproduce the original from the transformed versions. The version that seemed the post practical was to create a cue for each sentence, and attempt to reproduce the original wording from the cue. Another was to scramble the sentences of the piece and try to put them back in what felt like the most logical order. These seem pretty mechanical and rote, but they tie into an overall approach Ericson lays out called deliberate practice.