Before you write anything (even a simple email), spend some time thinking about your reader.
This is the person you will be having a written conversation with.
Consider what’s important to them, what excites or scares them, what do they already know, and what do they need to know.
How do they like to receive information and how will they find your document – will they search it out or will you give it to them?
What will be their emotional state as they read.
Will they read a long document, or do you need to keep it short and to the point? Can they handle complex language?
And most importantly, what do they need to do with the document you provide, with this information product you are giving them?
Only after doing some serious thinking around these types of questions can you match your writing to your readers needs and wants.