Can you see the snow leopard in this picture? It's in the centre. Snow leopards are rather spectacular, yet the camera shows us that they can also hide in plain sight.
How clear is your purpose for communicating? The most common problem I uncover as a communication coach is that people haven't really thought through what they want. Like the snow leopard, their purpose is in the picture, but it's not easy to see.
The single most important thing you can do to improve your writing or speaking is to decide before every communication: what do I want to change in my reader or audience? What do I want them to think or do differently because I communicated? And then ask: "What will that get me?" Repeat the question until you're sure you've come to the deepest, best outcome for the email or blog post or presentation you are preparing.
When you give your mind/brain/body a clear description of what you want, that system is remarkably good at adapting to circumstances and finding what you need to get what you want. When you communicate, that system will choose your words, gestures, expressions and postures so that you make the most of what you have prepared. But your performance will only be as good as your words, gestures and expressions and postures. And those will depend on how clearly you have defined your outcome.
It's not enough to know that you "have" to give a presentation or that you have to "cover" a topic. Imagine instead, that the opportunity to connect is a valuable and limited resource. You need to get and to give real value each time you communicate. It's worth preparing not only your topic, but your best reason for speaking or writing.