HelloI'm afraid that almost no cars will produce the advertised fuel consumption figures, as these are obtained on a rolling road under very specific test conditionsthe advertised figures should only be used as a relative guide to other makes and modelsif you see this site herehttp://www.honestjohn.co.uk/realmpg/ford/focus-2011you'll see that a typical milage is about 50-55mpg from other ownersthere's alos a few other things worth checking
Check that all the wheels can be turned freely by hand, and free off any sticking calipers
Incorrect wheel alignment:
Check all the tyres for signs of uneven wear if it has any then get it checked out at a place that does 4 wheel alignment not just front tracking and ensure tyres are pumped up to their recommended maximum
Injectors are clean and not dribbling - add a bottle of injector cleaner to the tank
Use good quality fuel - from my own findings its worth paying the extra for BP or shell as typically you'll get another 10% fuel saving which outweighs the cost over supermarket fuel.
And the biggest thing is driving style, by not labouring the engine ( too high a gear up hills etc) and not accelerating hard away from the lights etc you can usually improve things by another 25-30% or so.