One important thing to remember about cold calling is that you should use your "failures" to Build A Database. Let's remember you're contacting people (generally) at THEIR place of business and you don't know how distracted or busy they are. Often you're involved in your pitch and they practically disappear. Perhaps they've actually decided "NO" but likely they're just thinking about other things. I've learned that pressing ahead, i.e. "I just need one more minute of your time!" (hoping that the next thing I say will somehow be magic) just isn't very successful. So I will be the one to back away. "Bob, it sounds to me like you've got a lot going on so why don't I let you get back to business. Why don't we CHECK BACK WITH EACH OTHER down the road. Would that be all right?" He says 'sure' and you're gone.
BUT NOW you have his permission to "check back" and that can be another call two weeks from now, a letter reminding him of your advantages or... best yet... a "walk in" in which you knock on his door and say "we talked last week and I wanted to drop off that information. By the way, I happen to have my calendar with me, why don't we set an appointment get toether for 20 minutes. Does Tuesday at 10 look okay?"
Even if you don't set the appointment, this prospect is now part of your database and the more contact you have (seven 5 to 7 is considered the minimum before MOST sales are made) the better. You now no longer have a Prospect, you have a Relationship.