Looks, your voice, how you come across etc always plays a part.
if your asking cold then their likely reaction will be NO.
Im 28, i still get asked for ID when buying alcohol so i must look quite young - some even ask me if "do you actually own the business"..
Therefore I feel I have a problem to start with, so i personally do not like knocking. I feel im disadvantaged from the very start from my good young looks

So i make use of a well presented flyer - keep it short and simple. I drop they flyer and then re visit the area, with flyer in hand, so they can identify me (or the business from the flyer) from the very start.
Introduce myself, ask if they would like a quotation.. if they say no thanks, i thank them for their time, and advise if they change their mind in the future or have any need for any of the services i provide then to give me a call.
Leave them with a good impression, give it a few months you may get that call. Canvassing is not easy, and you get a lot more rejections than you like (you have to be good at rejection to do it).
it takes time to build up a decent round.. it might sound easy but its not.