I use splines to model a top-down 2d framework, then fill it in with polys, attach and weld verts, and then use either a derived measurement or z-coordinates to give my object height. From there, any detailing can be done either in 3d space or as a new framework using the old one as a reference. I find thathide and freeze tools are quite helpful in conjunction with the group-selection capability (shapes, geometry, etc). I know I work quite differently than everyone else, but I enjoy it, it lets me get to know what I am modelling a bit better, and it also means that if I want something modeled, I have to be able to 'draw' it before just going in with random tools that I think might work.