As you have seen, I put a lot of effort into basing my models. Although this is a WW 2 piece, the same technique can be used for any tabletop game.
While battlefront has made some fantastic urban rubble bases, they are too expensive to use on large units. For that reason, I came up with a way to make my own.
I bought a sheet of styrene plastic with a cobblestone texture, and cut it to the right size to fit the base. I glue that to the base with super glue.
Step 1: After I primed the base, I basecoated it with VMC English Uniform. I did a lot of experimenting with base and ground colors, and I have found English Uniform to be universal. I had a gallon of the color mixed up for me at Home Depot, and I use it to basecoat all of my terrain pieces.
Step 2: I mixed up some texture gel, small rocks, and bricks that I made by cutting really small plastic stock (.060 x .125). I colored it with a few drops of English Uniform.
Step 3: Brush the mixture around the base and let it dry. be sure to leave some of the spots bare.
Step 4: I heavily drybrushed the base with VMC Khaki.
Step 5: Lightly drybrush it with VMC Buff.
Step 6: Here is a closer view of the base so far.
Step 7: Now we add some contrast to the base. I paint the small rocks with a 50/50 mix of London Grey and White. I painted the bricks with VMC Light Brown (I think...any earthy red/orange works)
Finished! Clean up the edge of the base with English Uniform and add your troops. This is a British PIAT team.