the spanish do not have their windows cleaned, as much or as regular as the british, germans or any of the other nordic countries.
most commercial work is taken.
most residential work is very very difficult to win, and usually only if you do it much much cheaper
most windows have bars, shutters etc making manual cleaning very labourous.
you drink nearly a litre of water every hour, when its warm - when its hot you cant work.
if you work for someone else, be prepared to work 10 hours a day, fe if any breaks, use your own transport materials ladders scrims etc etc AND you can and probably will be woring irregular hours and days for about 50 euros a day... if your very lucky.
forget wfp as using water for anything other than drinking is banned...
you pay a flat tax, so even before you get your first customer you need enough money to pay your taxes.
probably will take you 6 to 12 months to earn 1000 euros per month.
thats just a few pointers... coffee is nice though!