Rarely are characters alone in a scene without a phone, a knife, something. People talk with their hands and bodies as much or more than their mouths. Not a word has been said, but a message has been sent. This kind of indirection is an extremely valuable tool for effective and stylish storytelling. Make props a part of the scene.
Motion is good.
Next, tag the characters themselves. These tags help us not only to visualize the person, but also to identify them. It's dark in a room and the main character cannot see. We don't have to identify the speaker now. This is especially good, because we're inviting the reader to fill in the rest.