Ron Lemen explains two approaches to figure drawing - observational and formulaic. The observational approach uses sight-size methodology and tools like plumb lines to capture accuracy, while the formulaic approach uses abstract shapes to construct figures. Lemen focuses on explaining the Reilly method, which builds the figure from its core structure and adds anatomy and details. The Reilly method establishes key lines to define the pose before adding arms, legs, and muscle groups to complete the figure. Mastering this system allows artists flexibility to create figures from different angles.