Here's a glimpse into my ideation process. I am a visual thinker. The sketchbook helps to create rungs in the conceptual ladder. A feedback loop occurs between depiction and description: A doodle prompts labels, many of which in turn spur more drawings. The graphemes and lines expand outward, filling the page like bacteria in a petri dish.
Brainstorms like this are often disposable. The instantiation process is often more important than later review.
The drawings are tiny, each page was 5.5" x 8.5." The reasons for this size is:
1. It's faster: less distance traversed
2. Brainstorming works best with plenty of room for labels and expansions/iterations, so item size is ideally a fraction of a page. Portability constrains page size to 5.5x8.5, the same size as this book.
3. Keeping small constrains the design to what is essential, preventing unnecessary detail. The visual looseness keeps my creative mind pliable.
I used generic ballpoint pens as well as the classic 4-color retractables for most of the work in this section. Lack of erasability is plus - it fosters iteration over unnecessary rework. The "inkblob" artifacts prevent me from dwelling too much on perfecting the linework, and can often add a unique character and sense of life to the overall sketch.
These are from a few years ago (2015-2017 ish). I have since been doing most of my brainstorm work in on loose leaf paper and digitally on my tablet.