1. Never deny a negative
This is a tricky one because I know the first places your thoughts go to are the negatives that you feel they have brought up or those you are harboring against them. You need to focus on the negatives that get in the way of them making a decision. When you are trying to decide what those are, think to yourself “how do they describe me behind my back, when there is no way the description would get back to me, what do they say?” That is what needs to be articulated by you.
The second aspect of this is, of course, is phrasing. Never say “I don't want you to think I'm a jerk.” That is a denial of the negative with using, “don't think.” Instead say “it must seem like I am a jerk,” or even “I am a jerk.” This is hard for us to do because we are taking responsibility for something we may not agree with. You don't need to agree to execute tactically. Plus no matter what you think, their opinion is very real to them. If there is a negative that you know is lingering never let it sit. It will fester like an infection. If they were upset about an order that went wrong 2 years ago, guess what - they are still upset about it. Every conversation with them needs to start with “We know you were disappointed with that order, you shouldn't have to put up with things like that.” Until they stop you and say “No, no that's in the past.”
Stephen Covey is one of the leading thought leaders on this idea of seeking to understand first. In his book 7 Habits of Highly Effective People, Habit 5 talks about how people form their own opinions/perspectives AKA values based on their own experiences, religion, morals, etc. If you are negotiating with a counterpart and you can't simply articulate what those values are to the other side, how can they ever trust you? What would make them go to their team and say “yup, this person is the one.”?
The second part about forgetting your own justifications has more to do with eliminating distractions. If you are worried about how you will state your objectives, you are not thinking about what to label or how you can use a loss aversion in getting them to realize a position. Our justifications will be there in our mind when we need them. When you play a card game you do not watch the cards in your hand, they are constant and don't change. No, you, in fact, watch the other players at the table and try to decide why they played a particular card, you keep track of what has been played and use the process of elimination to decide what is left to be revealed. It is the same idea in negotiation if you are watching your own hand you are missing what is transpiring around you.
In the end, the ability to influence the other side's decision making lies in removing the ego or pride that is attached to a certain value. Once that happens you can navigate obstacles with the counterparts assistance. You would be shocked what people will do for you if they feel like it. As human beings, we are all inherently programmed to work together. Chris & Tahl’s book Never Split the Difference says in negotiation “ignore human nature at your own peril” because if internally they have their own justifications or standards that hold them back from making decisions, it's in their nature. You do it too, bringing theirs to the forefront first by verbalizing them yourself is how you make progress. You can then assert your own position. Just like anything, the sequencing needs to be right. This communication approach can be done in long and short bursts, depending on the communication effort you are looking to employ.
Assertiveness is a required part of the process, just like relationships and analytics of data. The way you assert, namely with aggression is the key. One of the things we teach is being assertive with No-oriented questions, prospect theory, or the use of a calibrated question. Personally, I like the calibrated question because it is an easy way to make the other side solve the problem. Being assertive by saying I want, I need, I have to have makes people sound like a child fussing over a favorite toy. It does not invite collaboration, it only boxes people in and eliminates autonomy and flexibility. Don't forget our required empathy precursor, for example; we might say “I have something to tell you that you are not going to like and it will make me seem like a jerk” -silence- “How bad of a position do I put you in by asking for X?”
If you approach all your communication efforts with these guidelines in mind, pieces of information that completely change your outcomes will constantly reveal themselves. What is even better than that is your counterparts will trust you with information. We are all essentially in the trust business. Do you want them trusting you, or trusting that if they don't get their money, their lawyer will make you suffer? One of our good friends and business associates says that when he actually started making huge strides in his business with Black Swan skills is when he stopped focusing on getting his point across and started focusing on how he impacted someone's mindset.