A lot of my sales jobs have been what some people call "door to door".
In fact, one of my first 'proper sales jobs' was selling gas and electricity for the biggest company in the field. Being honest with you... even I was slightly surprised I got it- but as in practically every job that's been decent in my life, it took one quick interview then they offered it to me.
Still, just before the job started I was wondering "But... how can you walk up to a random person's door and expect them to buy a service from you that could cost them a thousand pounds per year?" For sure, this kind of approach hurdles over a lot of 'sales theory'.
Thing is though, practically everyone in the UK could save some money on gas and electricity. And you have to believe that. Plus most people don't understand the industry much, (I didn't when I just started). So you have the chance to actually educate people, AND save them some money.
One thing I would say about this industry... it helps having a strong brand. Nobody is going to like everything about a company, but if they know who you are, you've got a much better chance.
Anyway, let me tell you my typical opening line, "Hi it's Mark from xxx, (shows ID badge), just a quick call..."
Let me explain that last part for you. Even one of my managers thought it was wrong, but it isn't :). You see, when people open their door they usually are at least a bit apprehensive. They're worried that you could stay there for hours, or that you might be trying to "take money from them". Beauty of gas and electricity sales is, you don't take a penny from them. All you're actually doing is saving them some money- so this phrase puts people at ease. Also, you're establishing the frame- this will be a quick call.
Usually, you can tell right away if you've got a chance of a sale. If you have, sometimes it's just a matter of building a "Yes ladder"... sometimes very simple...
"I believe we've supplied you in the past at some point, is that correct?"
"Yes." (You can usually tell from the body language here if they were at least satisfied with the service.)
"Great, well would you be interested perhaps in saving some money?"
Anyway, that's an example of how easy it could be... being really honest again, I would say that only happened in around 5-10% of cases of people you actively talked to, still happened though :).