I did all the rendering on my Windows machine. Although I was initially using OpenEXR to view the images, I switched to Adobe Photoshop CS after realizing that the contrast in the image when viewing with OpenEXR was very different from the sample images in the assignment.
As suggested in the assignment, I used fewer samples per pixel and a lower resolution in order to have a fast render time before arriving at the configuration of my lights and camera that I was happy with. Basically for each scene, I would work on one light at a time, and I would position the light according to the description and diagram for the scene, then render and begin adjusting the light's position and rotation based on the current image, especially the shadows. Working on one light at a time also improved rendering time. I also changed parameters like the radius of the area light, the intensity, and the cone angle for the spot light in order to get the image to be approximately the correct brightness and have the same shine on certain features.