One technique I often employ for drawing is to make constructive mannequins of figures to help me visualize 3-dimensional elements in a scene, and make sure they are in proportion, planted to the ground, and believable. When creating art without reference, this is essential so that costumes and props can be made to exist dimensionally and in correct relation to the figures.
Using this procedure, you can also adjust the figures if the art is on layers or sheets of tracing paper, and arrive at a scene that contains a greater degree of pose variety and complexity. If you then go to shoot photo reference for the figures, you can be sure that the poses are reproduceable by real people. The pitfall with this approach is losing the essential gesture of a figure, so make sure that this constructive method is always balanced with a bit of expressive distortion as you proceed.