Stereotypical salespeople are always selling. They're aggressive; they never take no for an answer; they are always supposed to be closing.
But your best salespeople know when to stop selling:
When You've Won
A sale is a series of negotiations. I want this; you want that. If I give you this, will you give me that? It starts from the moment the prospective customer becomes aware of your brand, and continues throughout your relationship, whatever the extent.
For the mathematically inclined, think of a graph of a sale, with its series of negotiations, like a 4th or 5th degree polynomial function that contains curves of various shapes and sizes, each with their own heights and depths of zeniths and nadirs -- depending on your perspective. The best salespeople know when they've reached an agreement "inflection point" in the negotiation function. Then they stop selling.
In a winning best case scenario example, you've given the pitch, they like the product, and you agree that they'll arrange another meeting to delve into more specifics, bring in a key stakeholder, they ask for a pricing sheet, etc. It's all good. Everyone's happy. You've won -- so stop selling! The best way to ruin the sale is to keep pushing. If you do that, you're effectively re-opening the negotiation. Mathematically speaking, you're taking yourself from the inflection point of a Sigmoid function, and changing the function to a downward quadratic (parabolic) one. In plain English: not a good idea. Here's why.
Think of the stereotypical grade grubber. He scores 96 out of 100 percent on an exam (a great score), but picks up on a comment in the margin from the professor and goes back to argue to recoup 2 of the 4 points he's lost there. A smart and justifiably annoyed professor responds to his request by offering to regrade the entire paper. And a smart and hopefully amused reader realizes that the grade grubber's score is likely to be lower than 96 in this revision grading scenario. Don't be a deal grubber. Stop selling.
In a winning worst case scenario example, you're in a tough discussion around deal terms. Your prospective partner concedes a big point, about which it's clear they're not happy. You've won -- so stop selling. Don't try make them or yourself feel better by trying to convince them they're getting a good deal and a great product. That's not why you won. You reached that winning inflection point because it's been determined they can't build internally, or that alternatives aren't as good, or you landed on the right side of organizational politics. Continuing to sell doesn't make you any friends, and it doesn't set up the eventual interaction for success. It means your victory -- and possible mandate -- is tenuous. So treat it that way and stop selling.
When You've Lost
Sometimes it's just not going to happen. Requirements are too far apart. They don't have budget. They want too much custom work. In salesperson speak, your prospective customer is "not qualified." You've lost -- so stop selling. Don't worry, you'll live to sell another day. One way you'll put yourself in harms way, reaching an even lower inflexion point, whatever the mathematical function, is by continuing to try to sell an unqualified prospective customer.
One of the worst sales people I worked with (as a customer) gave us some big concessions on some deal breaker terms we needed, such as pricing model and custom work. A few days after kickoff, we got a call from his CEO, begging us to unwind the deal because the company simply couldn't deliver on what had been promised for a number of reasons. The salesperson was fired. He didn't stop selling, and sold himself right out of his job.
One of the best salespeople I worked with (again, as a customer) told me upfront after our initial 30-minute phone call that there was no deal to be had. I agreed. It was a mismatch. The product as it stood and pricing model didn't align with my organization's needs at the time, and neither of us had a lot of flexibility. I respected that. When I did have the opportunity to work with him at my next company where we had different requirements and the product had matured, I made sure he got a call.
The previous two examples are more about product-market fit. However, like I said above, many times it's not about how compelling the product is, or the strength of your pitch, or the aggressiveness of your pricing. Just like that's not why you win, that's not why you lost. You lost for reasons that have nothing to do with you. Sometimes you'll hear that there's a new guy who wants to put his stamp on things, or the woman leading the department is opposed to buying versus building in-house, or you'll get word that a team is working on something similar, and that their jobs would be at risk if they engaged with you. When these things happen, telling them why your product is better or the price is right or showing them different collateral isn't going to help and may actually make things worse. So stop selling -- there. Escalate to someone more senior, try another team, or use that time for other more promising customers. Live to sell another day.
It's How You Play The Game
The best sales people know when they've won, when they've lost, and what's in between. That's how they close (good) deals.
So when you find yourself at an inflection point, stop selling.