Foreshortened objects can be a vexing problem for the beginning artist. The primary culprit for this is our preconceived notion of what a given object should look like. Consequently many beginning artists will struggle to combine what they see and what they think an object should look like. The result is generally not a good one.
An easy way to understand foreshortening is to envision your shoe in a, well, shoe box. A simple box in perspective is readily understood. The same principle applies to the shoe, or any object for that matter.
However, rendering a foreshortened shoe vis-a-vis a perspectal drawing is a daunting task. There are simply too many planes and variables to be dealt with.
The most efficient approach to drawing a foreshortened object is by accurately striking its arabesque. This encompasses both the shape and proportion. I prefer the term Arabesque as it implies gesture and dynamic relationships rather than Contour which implies a flat outline.