take a breath, observe your surroundings, and woosh move, it can be anywhere, half a centimeter backward or ten meters forwards, you are now a weeping angel so don't get caught moving
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.