I have a a5 sized sketchbook that I use for small drawings in colored pencil. It often comes along when I travel, and many of the drawings in there were created during long car rides. I tend to work to big when i try out new techniques and materials, and end up without the energy and motivation to actually finish. So keeping a small sketchbook like this is very helpful.
I did the landscape to try out a set of koh-i-noor polycolors i bought. They were pretty nice, soft and cheap. But the lightfastness is not as good as I would like and they seem to break easily. Oh well. There´s a lot of Derwent Coloursoft in there as well, and polychromos.
One of these is an exercise from a book by the way, the tomato. It´s from Masterful Color by Arlene Steinberg. I found it to be a very useful book, it thought me a lot more than I expected. Do you like to read books related to art? And do you find it useful?