I've been working through a translation course online and came across Grice's maxims, which describe "rules that operate in normal co-operative conversation." I liked them so much that I bookmarked the page (real book, real page, real bookmark). I've never had any reason to share them but I think they'd be very relevant here. I often think of them as "guidelines for communication" and as such, I feel like they fit my notion of "basic skills in the repertoire of a good communicator":
1. Quantity: Give the amount of information that is necessary. Do not give too much or too little.
2. Quality: Say only what you know to be true or what you can support.
3. Relevance: What you say should be relevant to the conversation.
4. Manner: Say what you need to say in a way that is appropriate to the message you wish to convey and which (normally) will be understood by the receiver.
According to the book (Introducing Translation Studies by Jeremy Munday), Paul Grice was a "philosopher of language." I like Chase's point that "listening to understand" is so important, as a communicator can't meet any of Grice's maxims unless they've taken the time to listen and understand the other person. It'd be nice if there were an equivalent to Grice's maxims for the listener's side of a conversation, but as far as I know, there isn't one.