This is great! I love how his outfit is rich with details, with a great variety of materials, while still being in coherent unity. I like how you contrast the use of brushes to establish this variety. And lastly, I like how you took special care of the face, painting it a more realistic style.
Thank you, first of all, I am a Chinese, my English is poor now, hope my answer useful to you, his outfit in the design at first, I read a lot of references, don't try so hard to determine his outline, When I don't know how to arrange equipment, will go find the history and description, and a lot of information literature about it. The pose is my suddenly inspiration. About the his face, I often consult one Japanese artist, he is good at depicting characters, his name is ながの つよし or Tsuyoshi Nagano or 长野刚