New member with some photoshop renderings of a chair

Hi! Being new to the forum I wanted to make my first post this one with some pics on. I am a noob when it comes to design, trying to understand it (will we ever?). Anybody can give me some universal design-ideas? I want to attent artschool but I am not sure of my level of skill. All my knowledge is from books and internet, no school. Maby you art-students can give me some pointers on what to include in my portfolio (for industrial design). I draw most things involving perspective (including human figure, my biggest passion). Anyway, here are some chair.renderings, quite quick ones. Btw the work on this forum is mindblowing, an honor to be a part of it!

best regards, Alexander

Sketched in Painter, rendered in Photoshop (wacom used):