I have done similes and personification and I'll do my best to describe the gesture the class came up with.
Statement: Similes compare two items using like or as.
Gesture: Lock hands together, interlacing your fingers like "Hands and Eyes", on the word "compare," separate hands and hold up two fingers, like a peace sign, on "two items", make an "L" using thumb and index finger of your right hand on the word "like" (it will look backwards to you) and an upside down peace with your left hand on the word "as" and place the left hand in front of the "L" so the thumb of the "L" is the crossbar of the "A" (upside down peace sign). You will end up with the Logo for the LA Dodgers. This may be a little gang-like so be sure you are using it with a group that won't be weird about it. My class (5th grade) and I refer to the Dodgers as the LA Similes instead of LA Dodgers.
Statement: Personification is giving human-like qualities to things that are not human.
Gesture: Pat yourself on "human-like qualities" (you can add simple gestures for qualities if you to demonstrate human motions), point to or grab items when saying "things", and waggle one finger left and right (like a mother warning a child not to do something) and slowly shake your head no on "not human."
Wow! Describing these things in words can be quite difficult. I hope these help. I haven't done metaphors yet but I'll let you know what I come up with when I get to it.
~Dave~