These illustrations are done in isometric perspective, which should be an easy way to work, but it can also be tricky. You don't need to establish vanishing points or draw all those convergence lines, but can be hard to force one's mind not to make lines converge, even though you are using a grid.
The advantage is that once you make an object (or character) you can place it anywhere in the picture, which is why isometric perspective is used in certain types of video games. Also excellent for maps of floor layouts. I based these drawings on my kids, cat and our house.
