When drawing a still life it is amazing how easy it is to forget the shape of an object when it is hidden or obscured by another. Half a bottle might not even meet the other half properly because we all get very involved in different parts of our drawing without looking at the drawing as a whole. It's useful to imagine you have X-ray eyes so you get the proportions of each object correct.
This is a very good exercise to help you when you draw a set of objects in the future. The example shown is simple and white to demonstrate the idea.
It doesn't matter what you choose to draw but you need to put your farthest object down first, draw it in line form and then add each object one by one from back to front, drawing each one overlying each other. Include all your working lines, i.e dropped axi, crosses and dots, it looks great.