I had my first time completing Inktober, this year!  I was thrilled. It was very difficult to complete my assignment some days.  The prompts that I used were from Instagram.  They were all adjectives like mysterious or fat.  I would do a quick Google or Pinterest search and then a quick sketch.  I wouldn't allow myself to use graphite but I do have a gray Derwent pen that I would use and then go over with a black pen.  My favorite image ended up being a landscape with a boat in the background.  For this one, I used acrylic ink and painted it on.  I rarely spent more than half an hour on a sketch as I wanted it to be a brief exercise.  I did watercolor on most of the days in October, as well.  I found that after watercolor, the sketching seemed so much more confined!  It was a great challenge.  I look forward to next year!