The Airplane is a WWII F6F-5 Hellcat, that I drew (on paper) for my class. The original image that i scanned, and the other two where color corrected in Photoshop.
(the plane was drawn by referencing this image:http://www.avionslegendaires.net/Images/Gf6f-2.jpg)
The pumpkin was drawn in Gimp by following the Drawing a Pumpkin in Gimp tutorial on Concept Cookie, and using my new graphics tablet (DigiPro WP5540 5x4"…Maybe someday ill get a Wakom) I bought the other day.
So I let my little sister try to draw in Gimp using my tablet… she drew a flower… and so after she was done i re drew it and came up with this. Didn’t spend much time on this, but i thought it was good enough to be put up here.
Well, your excellent 3d skills don’t seem to reflect your drawing skills. You need to Really focus on where the light is coming from and how it bounces off objects. I suppose I can’t tell you exactly how you figure it out, It’s more of something that you just need to realize. Also, working with colors is great, but for you, I’d start with just one hue (such as black) and use solely that hue but different shades to demonstrate shadows and highlights. I found that to be a good exercise. Also, nothing against GIMP (I love it), but I don’t find it the easiest program to paint with. I might also play around with different programs, and of course, traditional mediums.
Keep plugging away - maybe look up some tutorials on drawing, but in the mean time maybe look at using MyPaint for the drawing on computer - I really like the brushes and how they feel with my tablet.