Sketching the Composition

I want my vase and flowers to fill up the canvas, so I've cropped the photo by covering part of two sides with scrap paper, and then sketching in thin paint with a lot of OMS. As I correct the "drawing" and wipe off mistakes with a paper towel dipped in OMS, I'm also toning the canvas very thinly with a sienna coating. I already know that to try to make this a tight painting, it will take more time, so I'm going to do this loose and kind of "sketchy," a style I really like to work in. I'm only indicating major lines here, and getting the shapes down quickly.