Here's a neat little sales trick: when somebody is halfway on board, you give them a choice, but not between Yes and No. Between two different yeses.
"This car is great for you, would you like it in blue or red?"
"You and I will go out, would you prefer lunch or dinner?"
For one thing it's difficult to tell somebody that their question is wrong, it's much easier to just pick one. For another thing it takes away the responsibility of making the actual decision, one can pretend that has happened, when the seller is pretending it has. For a third thing it saves face for those who have a hard time letting the seller "win" by saying yes, if they perceive it as a contest.
Of course this gimmick is also good to know about on the receiving end, so one is aware of when it happens. :-)
Update: Timo said:
This is called the Alternative Close. It is one of the best known of all sales closing techniques. Sales literature knows tens of others, some very clever.
The more interesting discussion is where to draw the line of ethical and unethical salesmanship. Personally, I'm leaning towards the opinion that most active sales is unethical.
Yes, I agree that real "selling" is ethically questionable at best, since it assumes to know what's best for the customer.
And of course since it often embraces basic fakeness, you "put on" anything which will make the potential customer like you and trust you.
Interestingly, one of the best sales people I know, a lovely woman named Eva, who is always ahead of the pack in her large organization, doesn't seem to use any sales techniques. My guess is that her 100% belief and her inner and outer beauty does all the sales for her.
Update: Bruce points to this comprehensive list of sales techniques. Or to be more precise, closing techniques. The "close" is how to end the sales pitch with a Yes decision.