Nice start to your sketchbook, I like the last one especially - nice stylization. In terms of critique I would suggest working on perspective for a bit and trying to establish more sense of depth through a more clearly delineated sense of foreground/mid/background, the images feel a bit flat at the moment. Hope that helps!
Thank you for the critique... It does help yes, and i too am aware of those points you've made. It's a slow progression but im slowly getting there. Im glad you like the last piece as this was a first for me! I was really pleased with how that one turned out. It was actually an art test i was asked to do for the company TEAM17 (worms)... I just hope that im on the right track to soon break into the industry!
You have some very nice work yourself! do you work within the industry?