Don't telephone people! Simple!
Door knocking on the other hand is VERY good. I could offer a thousand words of advise, but without knowing you they would be useless.
Basically, just relax, DON'T think about what you are going to say, just be yourself. If you think about what to say too much you will forget your lines and look stupid. Just cover the basics and allow the prospect plenty of opportunity to ask questions. Think before you answer and talk slowly - this gives you time to think and helps the person understand.
DON'T try to sell on the door, just have some information to leave with them plus all your contact details (business cards if you have them). By NOT trying to sell your service you will give the impression of trustworthy and non-pushy. This will help you!
Most of the people you will speak to will be women! Smart dress (NO Suit) and nice shoes, women notice these things. Don't stand right in doorway, don't invade their space. As a start off, you are not selling, merely introducing yourself, build trust and you will get business!
I live in the cotswolds and leaflets to a tiny hamlet with say 10 houses is a waste of time, so I knock doors. I can identify well off residences and wealthy people. When I first started I tried to sell, got nothing! After a few days, changed track and just went to give info and introduce myself... as a result I started getting bookings. I rarely do more than one job a day, but spend a LONG time on each job, as a result charge a premium.
At the end of the day, you build trust and they will call you rather than some other number in phone book!
And ENJOY speaking with them!