Style comes through practice.
Style is basically the end result of drawing alot and falling into your own rhythm. The shapes Dan uses just come to him naturally, its why its hard to explain. Like said before its just like hand writing. it evolves on its one while you work.
Basically any question you can ask about improving in art is answered just by drawing more. Draw what you see around you.
If you like someones style then incorporating some of it into you work is a good idea, BUT trying to learning only from someone elses art will end up actually hurting your drawing skills in the long run