Help me improve my texture

I am working on getting better at doing materials for a scene I am working on and here is an example of what I’m working on, that I’m wishing to perfect.
Currently it looks good but I can’t get the spec to look right.
I’d appreciate some feedback so I can improve it and my skills.
I’ve used Blender for a few years however I’ve never gotten very deep into materials.
Here is test render of it :
http://img36.imageshack.us/img36/7646/rusttestrender.jpg

to me i think it needs a bit more spec and proper lighting