/ic/ - Artwork/Critique

The work of James Jean is just killing me. How to I even begin to learn making these beautiful, flowing, naturalistic lines? Is there a book or Video on some similar process?
He often uses naturals stuff like clouds, branches, leaves, wings, water splashes as almost abstract compositional elements, but they retain their convincing, 3D form. It's like I can't even come up with a single piece of cloud form as intricately beautiful as (for example) the cloud flowing form the characters mouth in picrel.