Ferriss's four-step method involves deconstructing a skill to its essential parts, selecting the most valuable factors to learn, sequencing and setting stakes to motivate you. This is very similar to Josh Kaufman's technique to learn anything in 20 hours.
The most interesting part of Ferriss' "4-Hour Ethos" is the sequencing. Scrub to the 15:25 mark to hear him describe how sequencing works. Essentially, think about practising in a different order than conventional wisdom might recommend. For example, learn chess by practising endings rather than openings, or, as Ferriss did, become a tango champion by studying the traditionally female role, which is less complex than the lead role. He also recommends "no stakes" practising: don't try to learn to cook when you need to get a meal on the table, but rather some other time when you have less pressure.
It's a nearly 25-minute talk, but one that could give you ideas for tackling that next skill you want to acquire.