Try not to repeat yourself from previous PA's. Imagine that you are writing an essay on the cartoon. The paragraph is just one of several.
In addition, try to work in some informal language. Don't be afraid to use texting abbreviations, but don't overdo it. The idea here is to achieve a moment or two of the informality in Chapter 9 of TSIS, but remember that you are still doing academic writing. You're looking for the prof to chuckle a bit and (maybe) forget that s/he is reading a big stack of essays at 3 AM.
Try to limit yourself to a single element of the cartoon and a single point of refutation, but develop each point completely. DOWNSHIFT.
"Git this thang" posted by Sunday at 5 PM, and try to look over other students' paragraphs before class on Monday.