The best writing advice I have is to separate your thoughts as you write them. Make them separate paragraphs, even sentences. Keep a vision, a theme in mind, as you go. Think about what you want to convey and how you want to convey it. And then let the words flow.
Because writing is like putting together a puzzle. The words are the pieces and the complete puzzle is a thought. Don’t worry about how it’s going to flow as you begin, that will come. Just write as your thoughts appear. And they will appear, because it is the nature of the mind to create thoughts, sometimes too many or to few, but it is one step you can rely on.
A lot of writing is opening up your perspective. Rather than viewing it as a task or chore, or allowing the process to be cluttered with thoughts of frustration and doubt, you need to look at it as a puzzle only you can complete. Then you go back and reread and move your pieces to where they fit. You will reread your piece many times, more times than you ever wanted to. It is a practice in patience and awareness.
You reread to see if you can say the same thing more logically, for word economy, for structure. You reread for grammatical errors and continuity. Then, and maybe most importantly you do NOT read it again. We can obsess to the point of destruction, so it’s important to have a friend or trusted colleague to pass it along to. Again a change of perspective is needed, in order to accept criticism with grace and a willingness to learn.
The person you pass your work along to should be someone you trust and that has your best interest at heart. Someone who understands and will allow you to accept the benefits of positive criticism. And once corrected, you let it go. In letting go you are putting your stamp of approval on it and opening it up to the rest of the world.