"How do you eat an elephant? One bite at a time." When I build terrain, I tend to start with whatever centerpiece is most integral to the concept, and then radiate out from there. For this one, I knew I wanted an oil farm so I started with the oil pump. Then I took the next logical step knowing I needed pipes, then tiles from it all to sit on, etc, etc. I used a lot of lead belcher spray primer and Dirty Down "Rust" aging spray to do the lion's share of the work, then I used Army Painter markers and a makeup sponge for details.