Clear communication is dead simple. Yet it drives conflict, consulting failures, and total confusion. Here's a few small tips for getting the point accross.
1. Tell them what they need to know. Don't tell them everything you know.
How do you know what they need to know? Listen!
Ask, clarify, paraphrase, and then answer exactly what they are looking for.
If there is additional information that can help them, then indicate that. But assess what they need to know for the purpose of this presentation / discussion.
2. Over talking (aka Waffling) is always ego based. Either because you are a show off, or because you are insecure. And it doesn't help in either case!
Don't use ten words where three will do. They won't be impressed, they will be confused or frustrated.
3. If you have a lot of information to relay, don't write it in an email. Walk over, or pick up the phone, and tell them. Discuss the nuances. Emphasise the risks/benefits, and make sure everyone gets it.
Nobody reads the email anyway...
4. Don't say sorry. Ever! Sorry won't fix anything. If you are saying sorry then something has already gone wrong. Try to get to the point where you don't need to say sorry. (Not really getting the message across - more like eliminating the need for the message!)
5. Don't assume, listen. I have taught over 3,000 people in one particular field of reliability engineering and every course somebody asks me something I had never thought of in my life. Try to understand their perspective.
6. Draw. Talk with a pen in your hand. I speak two other languages. When I was learning these I used drawing regularly to indicate concepts, facts and to communicate things I didn't have the words to express verbally.
7. Tell stories. Always tell stories. People have an almost primal reaction to stories. Parrticularly if it references their situation, thoughts and world view.
8. Just the facts. Ten anecdotes does not data make!! Do not make it up, rely on opinion, use unjustified anecdotes, or baseless statistics. Have the facts at hand in case you need to support what you are saying.