Apparently Morandi had a complex method of composing the objects within his natura morta paintings.
This is pretty fascinating, given the grosso modo appearance of the paintings.
I've read that he used grid systems and arcs in his layouts of the models and so forth, to achieve some sort of quasi-mathematical balance. Something that puzzles me, in light of this, is his signature. It is often relatively large, and so needs to be considered as a compositional element in itself. Hard to see in these cropped images, but sometimes they're left, sometimes centre- I always look for the signature and note what he did with it in each instance.