If you really want to see another excellent resource on this subject, not trying to dis the tutorial section, check out from your local library system or pick up from amazon.com a book specifically about creating model dioramas called
How to Build Dioramas by Sheperd Paine. It is AMAZING. Make sure you get the second edition though. The first edition is excellent, but the second is that much better. Anyhow, he goes over EVERY detail of planning, creating, detailing, lighting, photography and whatever you can imagine and even things you did not think of, for dioramas. I just bought the book earlier this week after drooling over my library's copy of first edition. Yes, almost everything he deals with in the book are World War II or other historical genres, but 99% of it translates quite well.
My favorite is the one with the broken tank and the soldiers digging a trench underneath and using the tank as a fighting position. Copying that but with a Rhino and some space marines could be tricky, yet awesome.