Deliberate practice is just this: performing your skill (or, more typically, a piece of it) monitoring your performance evaluating your success figuring out how to do it better and then repeating that sequence again and again. That’s it. That’s how to become an expert. Most experts have done just that, for hours a day, for years. Most of the information here is based on K. Anders Ericsson’s paper The Role of Deliberate Practice in the Acquisition of Expert Performance. That paper has data for violin players, piano players, chess players, gymnists, runners, tennis players, and swimmers. The domain doesn’t seem to matter–deliberate practice is the key developing expert performance.