Several people asked me about painting freehand and what preliminary work I do before actual painting starts. Here I put several sketches that I made before I started painting.  I try to do initial sketches roughly “in shape”. Since the cape flaps are approximately triangular I do all sketches inside a triangular area that approximate that cape flap. 

 
It doesn’t work always as intended. The variant that I thought to be final (circled) turned out to leave a lot of empty space in the upper part of the cape; therefore I had to change the position of the wing (on the next picture)

Same for the left flap. This is where it became apparent that I have too much of empty space above the dragon so I had to change the position of the wing. The two smaller sketches are actually painted; the bigger once are drawn with a pen on the train, so they are somewhat shaky :)

The inner surface was actually easy. I tried to combine in one design stylized wings and flame. The very first version was very much like bat wings painted inside the cape (I am sure I will recycle this idea on some vampire), that eventually got transformed into the final version literally in 2-3 iterations (all shown). The color version was actually painted; the rest is a colored pen, most likely also sketched on the train.