I make an effort to take at least 5 minutes each day and just sketch... usually with my mouse in photoshop. Sometimes I forget, and sometimes it turns out so terrible that I don't save it, but I save most of them (even with small mistakes), sort of like a doodle diary. I change up my brush type, give it odd filters, or play straight with textures sometimes, too. It's a good way to practice both my mouse-drawing and using my preferred image-editing software, Adobe Photoshop. Sometimes I go straight to MS Paint, or use GIMP, or do it the old fashioned way: pencil and a sketchbook, or corner of my notebook.
These are a few doodles I made this week.
I do recommend that, if you like drawing at all, to take the time to sketch each day, even if only for 5 minutes in MS Paint. It's fun and a good break, and it doesn't have to be perfect (or so I keep having to tell myself)... because you're just drawing for yourself.
Try it :)