Use a moderator to control the interaction. Consider outsourcing the technical aspects of the conference. Consider digital to analog transmission for video. Be aware that the security is no more than a telephone call or a fax transmission. Behaviors for Computer-mediated Conferences Less is often more.
Less motion is good.
Avoid humor, obtuse or inside references, and personal references. Stick to the agenda. Be aware of copyright laws for presentation materials. When using static visual aids, consider using a whiteboard shared application. Be aware of languages other than English which may need a higher bandwidth for voice.