I find my self needing to sit in a chair and stare off into space from time to time. I may close my eyes but I do not go to sleep. I simply sit and be. If I want to clear my head of thoughts I will think about my breath coming and going and when I do this I find my self settle down into a space that feels very large and forgiving. It is when I am in this mode that some of my best ideas come to me.
On the other hand I also receive wonderful ideas while I am in the midst of working, the work could be washing dishes of it could be looking for a particular drawing in my flat file. I don't have a formula and I'm not looking for one but I just know that I need both, activity and contemplative rest.