Google these peaple they will take your Art to the Next level I think you can learn many things from their works

Inoue Takehiko -Made the comic Slam Dunk and one of the newer comic Vagabond his art looks realistic makes commercials for TV aswell has a studio named I.T.Planning works for Shonen JUMP, Morning KC and more..

Masakazu Katsura -Creator of comic Denei shojo, D.N.A, and I"s really good at drawing female characters, Works for Shonen JUMP

Morita masanori -Creator of comics Rokudenashi Blues and more recently Rookies good at drawing realistic characters owns STUDIO HITMAN, Works for Shonen JUMP

Kazushi Hagiwara -Made the comic Bastard very very detailed work amazig anime style work. Works for Gekkan JUMP (monthly)

Tetsuya Nomura -Working for Square-Enix creator of game characters made Final Fantasy 7 characters and FF10,FFX2 characters more recently works on Kingdome Hearts series. Also did Dierge of Cerberos and FF7 the Movie.

Masamune Shirow -Very talented at CG art work known for his works such as Ghost in The Shell anime.

Miyazaki Hayao -the firs one in Japan to get highly reconized award for his anime movies despises getting called the Mr. Disney of Japan made works such as Nausicca, Totoro, Majyo no Takyubin, kurenai no buta, Mononokehime, Spirited away and many more...creator of STUDIO GHIBLI

Hyung-Tae Kim -Korean character designer very tallented in CG art work very young guy with talented skills keep a eye on this guy in coming years. Did character Design for game Magnacarta.

Toriyama Akira -If his Dragon Ball series didn't Blow up into the world many other anime would never have made it into the states. Also works for Square-enix and Shonen JUMP, owns BIRD STUDIO