When you do these are you starting with a free hand line drawing to solve perspective issues early on in the drawing or are you massing in shapes with more of a marker type brush and tightening down from there? I'm curious because I've been trying to start with former of the 2 and everything tends to mush on me.
Kind of both. A very rough line sketch to put the idea down on paper, followed by 50% opacity fill to get the out line shape clean. Then I go to town on separate sections to get the details right. I do a lot of editing on the initial shape as I go and try not to get too attached to detail I've already put down. If something doesn't fit it has to go. In this case, the pilot arms are obstructing some rather nice looking tubing that will never be seen again.