Next is the tricky part. Move your camera (first from the top view, then left or right) until the viewport grid (ground plane) matches the grid you created in your reference image. Make sure you maintain the match between the horizon lines.
When you believe you have achieved a match, create some dummy geometry to represent the structures in the scene. This will allow you to see the accuracy of your match. A plane on 0,0,0 (your viewport plane origin) would be your ground plane. Tweak the lens/field of vision (perspective) as necessary.

 

Almost there. Note that you do not need to match your grids perfectly, just the relationship between them. The Yellow lines are our viewport grid lines.

 

There are a number of variables that will effect the accuracy of your match. If the focal length and the perspective of the virtual camera and the reality camera differ, there will be deviations between the two.

 

Now that you have your camera placed and your dummy geometry in place, you can approximate the lighting. Here is a simple way to visualize the general location of the light source in your scene. Match a point in the scene with the same point on the shadow. (these are represented with two yellow arrows) Connect the two points and you will have the direction of your light source.

 

 

To further add realism to your composited elements, make the color of your shadow match the existing shadow color.

Our scene is set up and ready for our 3d elements.

Let me introduce a good friend of mine, the matte material. In 3dstudio, the material is called the shadow/matte material. We will assign this material to our ground plane, in order to 'catch' the shadows of our composited items. (make sure you have accept shadows on) An example of how the matte material is useful is illustrated below. The matte material is handy when you want to mask out areas in the scene that your 3d objects move behind. Below, I built the extruded triangular roof element, and assigned it the shadow/matte material, then placed the ball behind it.

 

As a final note, it is an artform in itself to get your composited elements to blend realistically with your background. I will delve more into this topic in version 1.2 of the tutorial. Don't be afraid to rip textures directly from your image, as we did with the color vaules of the shadows. Use blur and pay attention to the saturation of the colors of your composited elements (I obviously didn't ;P)

As always, this is just one way to get the job done, it has worked for me and allowed me to do this type of work extremely quickly. Hopefully it will work for you. Enjoy.

-Bruce