As thought of by - I thought it was a good idea also to post up how I do plaid for the TMNT-U girl skirts. ^^
I know this looks a bit wonky, but this is just how I do it and I tried my best to explain things as best as I could. This is my VERY FIRST tutorial I've ever made so please by gentle. XD
Like colored pencils? I could imagine that you start with the lines and then do the base color of the skirt. At least that's what I'm thinking in my head anyway.