Most negotiation mistakes are invisible at the table: they happened earlier, in the preparation, or in the negotiator's own head. We like to think a deal falls apart for want of verbal fluency. In reality, it falls apart for want of method. A well-prepared but shy negotiator almost always beats a brilliant but improvising one. Here are the six errors I see most often among the professionals I train, and the precise correction for each.
Mistake no. 1: negotiating without a fallback
This is the mother of all errors. Walking into a discussion without knowing what you will do if it fails is negotiating with a gun to your head. Your counterpart senses it at once: your need to close becomes your greatest weakness. The correction has a precise name, the BATNA (fallback option): before any meeting, identify your best alternative should there be no agreement. A second supplier already approached, a client B held in reserve, the ability to bring the work in-house. A solid BATNA is not about storming out; it gives you the calm that changes everything else.
Mistake no. 2: letting the other side name the first figure out of shyness
We are forever told to "let the other person talk". True for information, false for price. Refusing to name a figure for fear of "shocking" your counterpart amounts to letting them set the frame. The first amount stated exerts a pull on the whole rest of the discussion: it is the anchor point. The mistake is not to anchor, it is to anchor at random. An ambitious anchor must always be backed by a justification, otherwise it reads as arrogance and turns against you.
Mistake no. 3: turning the negotiation into a clash of egos
Let me tell you about a case. The head of an industrial SME, let's call him Marc, is renegotiating an annual maintenance contract. The supplier announces +18%. Stung, Marc shoots back: "Out of the question, that's daylight robbery." What follows is forty minutes of tension, two people dug in, no progress whatsoever. In the debrief I ask him a single question: "What is that +18% based on?" He had no idea. He had argued against a figure without ever attacking its foundation.
We replay the scene. This time Marc uses objective criteria: "Help me understand. The revision index in our contract is at +4.2% this year. On what basis do you reach 18?" Silence. The supplier admits he had "rounded up to cover inflation". By anchoring the discussion on an external standard rather than on his own irritation, Marc brought the increase down to +6%, indexed to the real figure. Annual saving: nearly 9,000 euros. The lesson: you do not negotiate against a person, you negotiate against facts.
Mistake no. 4: talking to fill the silence
After a counter-proposal, the amateur presses straight on: they argue, they justify themselves, and often... they concede before they are even asked to. The tactical silence is the most underrated tool in negotiation. Once you have put your figure on the table, say nothing. Three seconds of silence weigh heavily: it is usually the one who breaks it who moves. Resist the discomfort. The void works for you.
Mistake no. 5: ignoring the other side's emotion (and your own)
Believing that negotiation is purely rational is an engineer's error. A counterpart who feels slighted digs in, even on an advantageous offer. Before you persuade, defuse: name what the other person feels through tactical empathy ("I imagine this renegotiation puts you in an awkward position with your management"). And when your back is against the wall, rather than refusing head-on, hand the burden back with a calibrated question: "How am I supposed to accept this increase with the budget I've been given?" You force the other side to solve your problem.
Mistake no. 6: conceding without a trade-off
Every concession given away for free devalues the deal and starves your counterpart: they simply ask for more. The rule is absolute, apply give-and-take: no concession without a trade-off, ever. "I'll accept your 45-day payment terms if you raise the order to 500 units." The pivotal word is "if". It turns a surrender into an exchange, and protects the perceived value of everything you give up. If the balance of power genuinely deteriorates, the withdrawal remains your last lever: pausing the discussion beats signing a bad deal.
These six errors share a common denominator: they are born of impatience and poor preparation. To sharpen your reflexes at no risk, train in the cold on the simulator, and explore the countermeasures one card at a time in the library of techniques.
FAQ
What is the most common negotiation mistake?
Negotiating without having defined your fallback. Without a clear BATNA, you give way under the pressure of your need to close. The remedy is purely preparatory: put a figure on your best alternative before you enter the room, and set your walk-away point. It is that threshold, not your eloquence, that protects you from a bad deal.
Should you make the first offer or wait for the other side's?
Making the first offer is generally advantageous when you know the market value well, thanks to the anchoring effect. Wait only if you lack information on the real price: in that case, let the other side expose themselves. But as soon as you anchor, always back your figure with an objective justification, on pain of having it swept aside.
