My favorite way to make a texture is to take screen shots of my model from above or the side, paste the screenie into PowerPoint, and then use the power point drawing engine to scetch the detales onto my model. I leave the shapes in out rageous colors and then screenshot the slide show. I then paste the screenie onto a base texture, leaving the once outrageous color as transpartent (in MS Paint). I do this multiple times with multiple shades of my base texture. If you examine some of my ships, you will be able to track some of the lines from one colored panel to another. The Hygira Plantia web site used to have an excellent tutorial on this.