One small area of improvement in this gag, is that I finally reversed my signature out of a background area with pure color, instead of putting a white stroke around it, as I had previously done. It's a small thing, but it makes the signature easier to read and a lot cleaner, graphically speaking.
The other big breakthrough for me on this gag was how to properly draw a soccer ball! Before this drawing, I thought a soccer ball was a series of hexagons. But after an hour of trying to make that work on the page, I finally looked at some reference photos and discovered that a soccer ball is actually a black PENTAGON, surrounded by white hexagons. Who knew?!