
In perspective, closer things appear bigger, but you can't just do it at random. You can add the floor with false perspective (where things don't get bigger) just by drawing the floor and putting the footprints in. Use a curve to show that the foot is flat on the floor.
Once the feet are "on the floor", you'll want to make sure his hips line with the feet, and then the shoulders. This will pull him off the page and ground him. Refer to the linked example in my last post. Notice how the hips and shoulders are at about the same angle as the feet?
I'm on my way out the door, but I'll put together a better example a little late.