No matter what the subject, thinking and writing are generally slow. Best to isolate a dedicated time for this activity. I find I can be much more productive if I've already talked and discussed the message with others first, no matter how prematurely developed The idea.
I also found that keeping a log that tracks project task progress/development, phone call/ meetings, email activity, and best of all learnings. The log I keep is manual, but could easily be automated, and linked to calendar, inbox and your 30-60-90 day planning record.
Organizing learning along the way, with simple annotations , makes it easy for me to track evolutions in ideas, valuable resources and where to locate them. focuse