The biggest thing to think about is the ground plane. Look for things that might follow the perspective that the figure is in. The newspaper in this case plays a big part in establishing the space she is sitting in. The type on the newspaper also helps to emphasize this and also starts to imply a sort of grid.
Also watch for things such as drapery that touches the ground. That piece of cloth, as small as it may be, grounds the figure as it falls off her leg then slides along the ground plane.
Looking for elements that show perspective can also help you if you are drawing a difficult pose or angle. In this case, the block the model was lying on helped me to decide how I would draw in the forms of the body. The block also serves to heighten the sense of foreshortening as we see it travel back in perspective.
Showing what the model is sitting on adds to the sense of weight, gesture, and drama. Try to avoid having just a floating figure on the page, especially if they are leaning or sitting on something.
It also doesn't take much to show the environment. In this case just a few scribbles in the right direction is enough to give us a sense that he is standing on the ground.
Try to get into the habit of always considering the relationship the figure has to its environment. It will give your drawings much more depth and believability and it is a good starting point for incorporating more story elements.