Sometimes it can definitely help to build an extended shape like Andrei shows above and then slice off some extra area of it.

But that can also just push some problems further down the road if you want to continue to build new pieces onto the model as well, if what Stefan showed was only one portion of the whole smooth blobby model and not actually the final full shape.

The way Stefan sketched out the shape for that very first screenshot by having a sort of outline hull of your shape is just not a good way to approach NURBS modeling for making big smooth surfaces, that kind of "non-rectangular topology outline hull" really matches the way sub-d modeling works.

For NURBS modeling it's usually best to make smooth surfaces out of one single big surface which can then be trimmed to give more possibilities (what Andrei shows above is a good example). But the more that your model becomes a large and complex all smooth skin it generally becomes more and more of a candidate for sub-d modeling techniques instead.

NURBS modeling usually works well when there is more of a kind of "component" nature to the model, and you have fillets connecting different component pieces together.

When you are trying to do one big complex all smooth melty looking skin with not very distinguishable components in different areas, that just does not match the NURBS workflow very well.

- Michael