If you have compositing software like after effects, photoshop, combustion, gimp, etc...I would recommend rendering in layers. You will have MUCH more control over the final output and you can achieve a much more realistic render.
I usually render the following layers/passes
Diffuse
Occlusion
Specular
Shadow
Reflection
Don't be satisfied with what you can do but rather strive to do the things you can't do!
Exceed Expectations!