As the psycholinguist Herb Clark has pointed out, human communication is optimized for small numbers of people to talk together face-to-face in real time. The further we get from this ideal situation, the more opportunities there are for communication to go awry.
Having difficult conversations is hard to do successfully under the best of circumstances. When you must have that conversation virtually, a little extra preparation can go a long way toward making the interaction feel more like it would if you were in the same place at the same time. First, you want to create a sense of co-presence, or the ability to feel as though you can interact effectively with another person. For example, you might consider using a phone connection for voice if you don’t have a great internet connection. Second, try to use technology like videoconferencing or Skype so that you can make eye contact and read each other’s expressions. Finally, to override the effects of distance, make your discussion as specific as possible. It can be helpful to take notes before a conversation so that you have particular examples to bolster your main points.