I've been experimenting with different lighting techniques and wanted to hear your opinion on this image.

Also, how important are the use of shaders in your scene? I've never used them before, but I have tried

them once or twice and unless I'm doing something wrong, I didn't notice any difference in the results

once rendered. Is DOF a simple integration or is it a learned skill through trial and error?

Without a doubt IMO, lighting is the most crucial part in rendering a quality image that has realism.

Here's a sample render, any thoughts or tips on what I could or should do with this particular image

to increase its realism?     Thanks guys.