TRSE: How To Draw Tutorials:
3D Advanced Course

    It always takes some experimenting (trials of error) to draw what is in your mind even if it means lot of sketching and erasing until everything look right. There are also times when it would be better to start over and try a different take on a pose. The "bubbles" are not only thing used in the 3D drawing, even flat shapes (like flat circles) and "stick-people" can be used too.

    This is how I play with a sketch, experimenting with the bubbles and shapes using the rulers, triangles and french curves until it looks right to me and you can see some trials of errors on some parts like her arms and legs. Notice how I used the flat oval shapes to outline her wings and I had to be very careful with drawing oval shapes with french curve to draw those kind of shapes. If it get too messy and I'm not happy with the sketch, I start over again by sketching on a new paper.
    This sketch is the result of much trials of errors and with this sketch ready, I can do more work on it like drawing darker lines to be traced with ink (improving as I go).

    It takes a lot of practice including plenty of trials of error to learn and master the 3D concept of drawing and using some forms of aids such as "bubbles". The computer programs, and cheaper tools such as rulers and French Curvess can help make such drawings bit easier. By learning the 3D concept, your drawings would look lot better and would prove to be useful when doing any animated shows or graphic novels. I do apologize for not giving a deeper coverage of this subject, but those tutorials were to challenge you to THINK and figure stuff out. That's how I learned to draw on my own. ^_^;