flyers work, if they are designed for your desired customer. many people dont always read them when first put thru the door and go straight in the bin, flyering as a 12 month of the year effort. recirculate them on a 3-4 month basis. Not everyone phones straight away many will put it to the side until springs comes around and the sun is out more..
Follow up calls is always a good idea - knock on the door with your flyer in hand. Many may already have a window cleaner - depends on how saturated the area is with window cleaners.
Ive put out flyers only to get calls 3-6 months down the line.
Business cards never worked for me anyway, but i do carry them around and always give one to new customers even though they have my flyer.