Suggestions with online session

[HypnoWraith]

Pardon me if this was answered in a long ago post. I've noticed that IM, Chat, and other online methods are often used for sessions between people on this site. In my experience, I've only done sessions face to face, so I'm not sure how to handle interactions without the visual feedback. Even webcams would be too low resolution to see subtle eye movements, shifts in body weight, etc. That being said, I'm sure there's tricks that you all have learned along the way. Any advice is appreciated.