If you have not checked out Art Academy Wii U Sketchpad on the Wii U of course, I would highly recommend it. 4 Dollars is a very reasonable price, and it really is easy to learn and get the hang of. It has lots of traditional art tools that almost work like the real things, so if you don't have it please consider it.
Now it's hard to go back to the black and white pixelated drawings on Miiverse because they're pretty different. If you want to see more of my art on Miiverse, one of the only social networks I use, search the Nintendo Network ID: MrPiggyJelly1337.