Foreshortening compresses a form along the viewer's line of sight — a pointed arm or outstretched leg looks shorter and wider than its actual length because you're seeing it end-on.
It's what separates flat, stiff figure drawing from figures that feel like they're reaching, punching, or lunging directly at the viewer.
Break the limb or form into simple cylindrical sections rather than an outline.
Identify what part of the form is physically closest to the viewer — that part will be drawn largest.
Overlap and stack the cylindrical sections toward the vanishing form rather than making them thinner.
Compare the empty space around the limb to your reference — foreshortened forms often have unusual, exaggerated negative-space shapes that are easier to judge than the limb itself.
Wrap a few lines around the form like rings on a tube to reinforce the sense of it coming toward you.
Use shading to show where the cylinder turns away from the viewer, not just a hard edge.
Photograph your own hand pointing straight at the camera and draw only the negative space around it first — it trains your eye to stop relying on “how long is this really.”