Writing is primarily psychological. First you have to have something to say. You need to be driven to reach out to an invisible audience, to solve a problem. You may even know your end point but may not know how you are going to get there or what you are going to expound on in the body of your text.
I never overly concerned about grammar (sic, the “fine editor” decided to leave this one as written!). I know I can or my fine editor, my lovely and talented wife, can go back easily and tell me this or that needs correcting. To be driven by passion, conflict is far more important. If the feelings expressed are genuine they will always come through no matter how badly written the piece is. Expressing yourself honestly and openly is what the reader responds to–not facile-ness. It can be well written and say nothing.
Having something to say consistently always means providing quiet time for yourself and being able to listen to the tiny voice inside of you saying: “this is truly what is important and I want to express that openly to someone.” Proverbs in the bible says: “Be still and know I am God”
I am not going to discuss the existence of God in this piece but there is no doubt that one must have periods of reflection to continue to write. Otherwise that person’s ideas will peter out eventually. One must let his/her mind roam. And that process is always psychological. And that process is always a precursor to writing.