I found in modeling 3D it pretty hard when I had no idea of what I was trying to model.
Here I show a couple of ideas I found that made it a little easier.
First lots concepts:
I drew these based on life and I added some exaggeration.
The pencil were inked over in blue and some tone added in photoshop.
Second a front and side concept
This was based on trying out lots of different ideas but with a fixed time to settle on a single idea. Really I just needed a front and a side drawing. A helpful hint is to use Photoshop guide lines to keep general things somewhat aligned (by having them aligned it makes 3D modeling easier).
Third a front and side drawing
This was made in illustrator. For getting the shapes I made primitive circles and used path tool divide on shapes so i could delete parts. To get those guide lines we just need the ruler available and we can drag from the ruler the guides. Check out more on illustrator path tools from the online tutorial (techassistnow dot com), I first learned about using the path tools from reading their path online tutorial.
Finally drawing ready for 3D
By using Photoshop's slice tool we can get the front and side drawings to be the same height. I found it a little tricky using the slice tool at first when i just created slices around each, but when I created one big slice around both and edited the widths it worked out great.
Hope this was helpful.