Behind the scenes footage is widely available for those interested in examining the making of VFX. This lot from Industrial Light and Magic (the Edison of VFX) is particularly valuable for the purposes of analyzing digitally manipulated footage. In specific I value the wide array of techniques presented in this 3 minute compilation. Therein you'll find visual examples of: compositing, 3D modeling, color correction, digital mattes, DI passes (a million of them), chroma key, green screen, and much more. You'll also see the various stages in compositing VFX into plates, process by process.
There's even a nice little lens flare at the beginning, completely manufactured of course, as there are no cameras, lenses, or real light involved in that part of the clip.