I'm a bit disappointed with this one, not for the composition but because the bright wall went all muggy and made the shot underexpose. You win some, you lose some, and you've just got to be aware of the conditions (such as a big white wall in your shot) and how your camera is going to react to them (i.e. say 'Wow - loadsa light, I'm gonna shut down here and low and behold, your lovely bright wall comes out looking like porridge)!

You often get nice triangular shapes up on walls, with a street name or number, a window of some sort, and another architectural element or curiosity which you can combine and play with creatively. Here the triangle's the number, the face and the window box, but the shot isn't very 'clean' with the window itself a bit too strong and the funny little thing at the bottom getting in the way, I see now in retrospect.

But in any case, the opportunities are always there - it's amazing what some people will put on the walls of their houses and apartments, so look up and learn!