‘Developing documentation, especially user-centred documentation, is not a one shot process. It is a continual process of successive refinement.’ (William Horton)
Another way of saying this is ‘There is no such thing as good writing – only good rewriting.’
So, expecting to generate perfect text on your first draft is unrealistic.
When writing in plain language we are always aiming to write user-centred text, and so we will always be refining our structure, words and sentences as we get feedback from our users, as we test our documents with the people who need to use them to do something useful.
Genuine feedback from users, often through formal user testing, is often forgotten in plain language writing projects.
Make sure you include feedback beyond just internal review processes.