A good way to come up with cartoons is to force yourself into a problem that you need to solve.
For example, I was looking for another Halloween themed cartoon, but, drawing a blank (no pun intended), I drew a vampire in a meeting to see what might happen.
Are they in the red? Is it blood red? Is the meeting in the middle of the night? Are garlic sales down? Up? Are the Twilight movies helping?
In the end, I decided that if I were in a meeting with an honest to goodness vampire, I’d be less interested in our sales numbers and more interested in seeing that “turn into a bat thing” they can do, so I went with that.