go around from place to place at garage sales and markets and find things that most people like to buy, purchase it for cheaper then the usual price, go on kijiji or ebay any websight you can sell things on and search what you want to sell and see what the average price for that item is. for the most part it will be more then what you purchased it for. now put your add up for the price most people are selling it for or a bit under that to make it sell quicker and you have just made a profit, you can start out small and work your way up to more expensive things!
look through your house and find things you dont use you cant even imagine how much money is just laying around. sell those things on a sales web sight( kijiji, ebay)
go on article websights and make a article like this one, sure you wont be rich overnight but while your doing other things this can be making you any sort of extra earnings.
go ask buildings if you can wash there windows monthly they wont turn you down everyone needs there windows washed once and a while!