My tip for this would be to look at the object(s) your going to model (in reallife or ref images) and try to break it down and view it as a 3D model. This type of observation (I found) very handy to be able to visualise what I wanted to model, especially non organic objects.

The approach to NURBS or POLYS would need to be your judgement call. I would do polys and convert to subD from that, other ppl would say NURBS, its really a personal preference.

Beyond that the appraoch is your own as there is no hard and fast rules on how to model a particular item.

As for the details this should be left to bump/displacement maps and textures. You don't want to over complicate your model. A good thing to rememer is...

"If you can't see it don't model it"

To make the item look thick add edges wher requred to give the idea of thickness.

Hope this helps.