I find working from scratch in photoshop frustrating as well...Love the shading on the left most character, but the photoshop one is real nice as well, the pose is interesting... The middle character...is e riding some sort of hoverboard like thing?
Though, maybe two things? They are both about the most left character. At first, her hips seem very big, or was that meant to? And the position of her leg.. It somehow doesn't seem to work for me (sorry!)
And the second one...
Her.. nipples ( ) are white?
But I love the shading in the first, I adore the pose of the second one and the third one i just... As professional as can be *wubs*
Learning how to draw women just comes from studying the form from life. It's good to study how others draw it as well but the negative thing about that is you might pick up the artist mistakes. If you have an anatomy book or pictures, study the way the the body works. Simplify parts of the body to grasp a better understanding. I learned structure mainly from: Books - Glen Vilppu and George Bridgman
The rest of what I learned was in school from various life drawing instructors. Every person has there own way of structure but if you can find your own way that working, then go for it.
Your ability to portray the expressiveness of the characters, and to accurately portray action poses and the flow of the clothing, not to mention the sheer level of detail on these characters really shines through again. The use of shading and the overall effect on the paper remind me of DaVinci's studies!