While your working with the dodge and burn tool you can alter it as you go over partucular areas of the texture by using the shortcuts. Alt+shift+w=Shadows Alt+shift+v=Midtones Alt+shift+z=Highlights This gives a bit more variation in the shading. I think one of the main problems is that texture fills dont follow the contours of the object and so look a bit false from the outset. There is a very good artist at the below link who uses a kind of combination of Dodge,Burn & Smudge to amazing effect, You may want to check him out if you havn,t already seen his site.He has a tutorial up. http://www.sijun.com/dhabih/