Although it's a sketchbook on my lap here, it's interchangeable with my notebook and diary. Between the three is how I plan.
Often the ideas stem from the sketchbook, then have notes scribbled about them in the notebook and then actions, deadlines, meetings, workshops, visits etc are put in the diary. All of this is done with tea😊
I also have lots of ideas when out walking, and driving. I often find going for a walk a good way to shuffle and sort the ideas into an order so they are easier to work through when I'm back in the studio.