One trick I learned from past mistakes is to draw the background and the girl separately then photoshop them together. That way if the girl turns out great and then I have a mishap with the background, or visa versa, it doesn't matter. The whole illustration will not be ruined. This doesn't always work, sometimes its too complicated a pose or layout, but in the case of the Zaji drawings I can do it. All the girls are simple standing or walking figures, not overly intertwined with a prop or background element, like my previous illustration for Material Girls shown below.
The girl and the drape of her dress were so effected by the chair that they had to be drawn together. However it was a background I was very comfortable doing, as I have done a few similar drawings with similar subject matter for them before.