One of the things that you want to do with NURBS modeling is to use 2D profile curves and boolean operations to form much of your model. As opposed to building the 3D wireframe and then trying to fill that in like you would do in poly modeling.

Check out here for some tips for people coming from a poly modeling background:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4865.2

- Michael