You wanna learn how to draw cartoons? Go here, get the Preston Blair book, and start doing these exercises. They're the ones that master cartoonist John K uses to train his staff, many of whom have gone on to impressive careers in the LA animation scene.
Biggest help in drawing whatever style that involves human anatomy: Learn actual human anatomy. Do some life drawings, sketch from life, and you'll start to break down and understand the human body Learning how something works makes it easier to deconstruct and exaggerate, without it looking like a mistake over being intentional