Mexicans generally stand close together when conversing. Don't show signs of discomfort, which would be considered rude by your Mexican counterpart.
Mexicans often "hold" a gesture (a handshake, a squeeze of the arm, a hug) longer than Americans and Canadians do.
Don't stand with your hands on your hips; this signifies anger. It is considered rude to stand around with your hands in your pockets.