Very often when I start writing something, mainly notes for my work (I'm a researcher) but other times personal thoughts, I feel that my writing speed can't keep up with my stream of consciousness.
Just to give an example, I was writing down on my notebook a question that I wanted to post on interpersonal.stackexchange but, as soon as I started with the main question, I ended up thinking about all the details that I want to add. I became frustrated at my inability to produce something and after a while I stopped writing (which pushed me to write this post).
In addition, I usually keep rereading what I've just written again and again and again, and keep changing it but without adding much to the subject. I think I spent more than half an hour to write down this question.
Apart from writing more and more often to train the "writing muscle" what would you suggest to avoid this situation?