Mayo goes on the bottom of the top half of the bun. It's thick enough, it doesn't soak into the bun. Lettuce goes next - it'll attach to the mayo. Then, tomato slices on top of the lettuce, so you can put your thumbs on the top of the bun as you flip it over to help hold the lettuce on the bun.
Now, on the bottom bun, you got your patty, cheese, then ketchup - one spiral ring (three loops wide). Four pickles, not overlapping (unless they're big slices) and a small handful of sliced onions.
That's how you make a Whopper.