I've been keeping an active design book for the last 3 years. I buy the largest spiral bound artists sketch pad from the local art store that fits in my backpa

I've been keeping an active design book for the last 3 years. I buy the largest spiral bound artists sketch pad from the local art store that fits in my backpack (usually $16-$19). I go through one a year. The notebook is for ideas, concepts and stories. Day to day notes are done elsewhere. Opening the notebook immediately puts me in the right mindset. Each page get's it's own idea or subconcept, though some pages are just a mix of smaller ones. I'm not afraid to be messy, to write in different size text, sometimes bold, for important items. I write 'idea!' in large text for new worthy ideas. I also use good felt tip pens also from the local artist store. I get a set of 5 from 0.1 to 0.5, and usually write with 0.3.