Concept artists to look at:

Whether or not they relate to your concept art or book, you owe it to yourself to look these guys up:

Henrick Hansen
(Mini Ninjas)

Shinkiro AKA Toshiaki Mori
('CAPCOM vs' series)

Istvan Pely
(Fallout 3)

Ryozo Tsujimoyo
(Monster Hunter Series)

Tatsuya Yoshikawa
(Breath of Fire Series)

Aaron Garbut
(GTA series)

Edward Pun
(inFAMOUS)

Mike Haney
(inFAMOUS)

Victor Antonov
(The Orange Box)

Moby Francke
(The Orange Box)

Jay Epperson
(Henry Hatsworth In The Puzzling Adventure)