I started building the fence first. I used the pen tool to draw a simple shape for the one of the slats.
Next, I wanted to give the object a little dimension, so I selected Copy (Command + C, or Control + C on a PC), then Paste in Back (Command + B). With the background object still selected I used the arrow keys to nudge it over to the right a little bit until it looked like this:
There I had my first fence slat. I copied the object several times. In Illustrator you can do this quickly by selecting the object, then by holding down the Option and Shift keys while dragging the object to the right to create an exact duplicate of the fence. I did this several times, then added a long skinny rectangular cross-beam on top until the finished piece looked like this:
I repeated this process for each of the wood slats until I had the entire fence built. After that, I went back in and reduced the transparency on each of my wood texture shapes. Then I used some custom brushes I've put together over the years, and painted over the wood textures so that they blended into the rest of the illustration. Lastly, I painted some shadows I on a Multiply layer. The complete fence looked like this:
I did much the same thing by pasting in some brick textures into the main structure of the brownstone. This saved me a ton of time I would have otherwise had to spend paintstakingly rendering each individual brick. If I'd had more time I probably would have done just that, but time was at a premium and even by taking these shortcuts, I still ended up finishing the illustration with literally minutes to spare before my deadline. Ivy was happy, which of course made me a happy boy as well.