Attached Link: From My Own Little Gallery

("A Self Referential Don't Touch") - about a 26 hour (network)  render, as I recall.

In addition to the above excellent advice, I'd add the simple, yet often enough overlooked by some,  importance of using a suitable rendering quality. This does not mean Vue's previewlike "final" setting.  My own attempts at realism, successful or not,  usually entail a great deal of time spent creating meshes, texture mapping them, etc., in addition of course, creating an interesting and hopefully creative composition. Given this, why in the hell would I insist on a quick render?

Most of my own work is rendered at a custom setting which is similar to, but a bit better than "broadcast." The images are rendered out very large - usually the width is in the 2000-2500 pixel range. This gives me the advantage of a rather good quality render at a size which allows very easy pixel level post-processing if needed.  (usually very small scale  softening or blending, or the repair of artifacts of bad vertices or something.) Residual depth of field graininess, soft shadow imperfections, and better quality antialiasing are neatly taken care of during resizing to a more managable display size of 800x600 or 1024. When using GI, HDR, (or God forbid, volumetric lighting, radiosity,  perhaps with DOF blurring thrown in to really put the brakes on things) this can result in very lengthy render times, sometimes several days, or even more, even when networking several machines. (I usually use 3 roughly similar machines). But why hurry? What's the point?

"La meta es el olvido. Yo he llegado antes."
Jorge Luis Borges,Un Poeta Menor,Oro De Los Tigres