I started with the wall and pavement, and did as is natural for an alleyway - made it look nasty, grimy, and run down. For the concrete frame, I used textures over each other; the green mildew ridden concrete over a cracked and lichen covered concrete for example. Using the eraser I created areas of low detail to contrast this so there would not be a detail overload for the player.
I did much the same for the brick wall - adding in peeling, painted areas from another texture and areas of plaster work. I'm very happy with how it came out.
The concrete pavement was easy and used many of the techniques I used on the concrete areas of the wall. But I used an image of chiseled stone, put it into grey scale, and added it as an overlay to create depth. I added shadows around the drain covers, and it was done.
Next was the barrel, which was simple a wooden plank texture with the chiseled stone overlay. The metal strips were harder, as their placements were not made obvious on the template, but came out looking wonderfully rusty. After that all I had to add was shadow and some flaking paint.
There were other simple things to do as well, such as the drain pipe and slats over the window.
Next up were the bump maps, which involved desaturating the colour of the textures until they were in grey scale.
Once all of this was done and applied to the model, it looked like this!
I am very happy with the finished result - the textures work well in the flesh, aside from the manhole cover, I fear I added too much shadow to it, but overall I feel this was a success.