The entire point of a risk assessment is it will be different in every area you work in, most can be found online to show how you need to view the place you are working, but as a rule think a complete moron walks into the area you are working,
What are the risks to the public, wet floors, trip hazards such as cables ect. What are the risks to your staff the same as the public such as falling over cables but also are you cleaning windows , do they open will they reach out to clean, how high are you cleaning do you use a step or a ladder ect. What chemicals or cleaning agents are you using, do you have kits in case of eye splashes ect? Do you need signs will you need cable covers? Quite simply for a communal clean you should take into account any trip/slip hazards to the public, not break fire rules by blocking escape routes or wedging fire doors open and only clean in a safe manor no hanging out of windows ect. or using ladders wrongly on stairs.