Communication skills are so important that it's worth repeating! I've repeated it three times because there are three logical parts to communication. Of course, you already communicated plenty when you were a developer.
You wrote emails, spoke on conference calls, and maybe even created reports and presentations and gave pitches.
Your communications have a different mission when you are a manager though. Your communications become less about explaining the logic or business knowledge and more about influencing and conveying visions, ideas, and concepts.
It's important to acknowledge the difference between a factual conversation and an opinion-based conversation that might be based on little or no information. For example, a project management meeting about the allocation of key resources is likely to be...