In reading some gestures and using them in the classroom, I've thought of a few ideas. One thing I think that can make gestures very effective is if they are similar to each other and effectively distinguish between related concepts. One example is the Whole Brain Teaching classic nonfiction(two fingers pointing at the forehead to indicate two eyes) vs. fiction (same, but with three fingers).
Another I used today that illustrates this idea was for two of our vocabulary words: tinker and repair. Both gestures were turning a screwdriver, but tinker was done repeatedly with a tentative/confused look on the face, and repair was done once and forcefully, indicating that while tinker just means casually attempting to fix something, repair means actually fixing it. Not sure how great that one is, we'll see.
What other ideas do people have about what makes a good gesture?