You may have an insanely awesome product, but if somebody won't even listen to your sales pitch, you're sunk. For difficult prospects who are hard to even talk to, you need to try it from a different angle. Instead of trying to get them to listen to your pitch, try and find a shared connection between you two. That will help you seem more like a real person, instead of just a salesman.
My first experiences as a salesman was selling batteries in a fundraiser for the Boy Scouts. In fact, they were just starting their fundraiser the very day that I joined. I was so excited to get to make some real money selling stuff door to door. To make things even better, the guy running the fundraiser was a successful businessman in the community who knew very well about sales. He taught us all that as soon as we introduced ourselves, we should immediatly say that we are members of a local boy scout troop. By saying that we are members of a local troop, we were instantly creating a connection with that person. Our location suddenly became a selling point, something to differentiate us from the countless other charities out there asking for money.
When you are trying to sell to someone who may be difficult to approach, take time to look for any points of shared connection between the two of you. If you are a small company selling mainly to people in your same city, capitalize on that fact by letting people know. Today with the internet, you can look up someone's profile on linkedIn, or their profile on their company website. You may find that they are avid football fans like you. Or you may find that they enjoy travelling like you do. They may be a software company, and you are selling software - there's a great connection right there. There are a million different possible connections you could find.
Once you find a shared connection, it's time to point it out. It may take as little as 10 seconds to say you are a local business. It doesn't have to be amazing but you'd be surprised at the difference it can make at just getting people to listen to your sales pitch. Next time you go out selling, try to find some simple way to point out a connection between you and your prospect, and see what happens.