I can't recommend this book (or any of his others) enough.
Swim with the Sharks; without being eaten alive by Harvey MacKay
At the age of 47, I switched into a completely new industry (and not knowing anything about it) and managed to survive "without being eaten alive".
I dont "cold call" anymore. I get referrals or drop a name, with their permission, to call on a new client. I can cold call but hate doing it. Now in my second year in this business, I get referrals to other customers, I do a lot of networking and I just try to treat the customers that i have, right! Do what you say you are going to do and do it before they expect it done.