Sit down.
If a odd bit has occured to me between sitting down periods, the note I scribbled it on is taken out and its contents transfered to a page.
If no odd bits exist, scribble down current events that need commented on or characters that I haven't done anything with for a while. Pick one that seems likely to produce something.
Come up with a bit of conversation or action for the topic/character. It can be the begining, middle, or the end.
Fill out the conversation so that the beginning gives the reader some idea was the strip will be about, the middle moves the action forward or contributes some interesting thoughts or pauses for comedic tension, and the end gives a twist that makes fireworks explode in the readers head or at least brings a small smile.
Flesh out the images for the joke.
