We'll focus here on gaining a buy-in to the solution of a suite of connected problems in an organization, the so called "minus the minuses" buy-in versus the buy-in to a plan to achieve ambitious goals (called a "plus the plusses" buy-in because the objective is to add the positive target outcomes rather than eliminate the negative symptoms). .
In this environment, the challenge is that almost any solution proposed is met by layers of resistance. The good news is that the layers are predictable, and the way through them is methodical.
These layers are not "touchy-feely." They are tangibe, and demonstrable. It's almost amusing to be involved in a situation where someone without knowledge of them, or the past through them, is presenting a good idea or even a good solution and achieving nothing but the triggering of the layers of resistance time after time. Unless, that is, the person is trying to make a case for using our services!
The Layers of Resistance
There are always several layers of resistance to a new idea; each has to be addressed in order to gain a buy-in.
Layer 1: Disagreement as to the problem. You are presenting a solution but the people you're working with have their own opinion even as to the problem to be solved, let alone the solution to it, and their opinion does not match your plan.
Very often this takes the form of, they believe the problem is someone else - the vendors, management, customers, the forecast, etc. They raise challenges and objections immediately that the problem is out of our hands, what can we do, your idea sounds fine on the surface and they can see how you could think that but ... etc.
Layer 2: Your solution isn't their solution to the same problem. This is basically a disagreement on the DIRECTION of the solution - you're not even far enough yet to have a disagreement on the details.
Remember, almost everyone who lives in the environment and who is touched by a significant problem develops their own pet solution. Probably not in detail. But perhaps they even mentioned it once or twice to co-workers or (rarely) even management and got shot down. Now, it's their solution, it's the only solution as far as they're concerned, and if yours is different, tough. They'll not only not support your idea, they will often actively work to prove you wrong - not because they are mean, but because yours cannot work, because theirs is the right one. Even worse they sometimes passively work to prove you wrong - saying "yes" while acting "no."
Layer 3: Even if the direction has merit, they are far from convinced that your solution in detail will solve the problem. This can be true even if they themselves don't have a pet solution in mind.
Intuitively they know there's a long way between a good idea (direction) and a good solution. The fact that they don't know how to bridge the gap just adds fuel to their belief that probably, neither do you.
Layer 4: All they see are the negative consequences, the negative side effects of doing what might otherwise be a good thing. Expressed in the form of "Yes but ... " objections, they perceive all sorts of problems from what you are proposing.
Layer 5: Too many obstacles. This also takes the form of "Yes but ...." objections, but they're a different form (and the difference is crucial, by the way). This time, they simply see too many obstacles to what you are proposing. In their eyes, it simply won't fly. Why getting to this point is particularly interesting is because it means they've already accepted your solution will work ... if only it could become reality. Now they're telling you why you can't put it in place; why it'll never become reality.
Layer 6: I can see the benefit but others will not. You may have succeeded in gaining their buy-in to the problem, and the potential of your solution to solve it, but it's still not worth their energy to climb on board because other, key people will not collaborate. They are bound to kill it.
There's another Layer 6 sometimes proposed: an unverbalized fear. They fully accept the problem is well defined, your solution will solve it, and your plan to put the solution in place is solid. But ... they'd still rather not change direction.
A solid buy-in has to overcome all of these, and (ideally) generate the emotion of ownership of the solution, too (in order to overcome the NIH syndrome).
You have to peel off the layers one by one. And it WILL take time. You have to do your homework, your preparation, which takes time. Then conduct the buy-in itself, which takes time.
However, the alternative is that you will expend far more time in trying and failing to get the buy-in and in dealing with the consequences of no buy-in or, much worse, a partial buy-in (say "yes," do "no" or say "yes," do nothing).
One more strong justification for the conscientious buy-in; if you are failing, most often you will recognize the failure early enough to bail-out and return with an improved buy-in and without loss of position. You can usually bail-out before they say "no I don't accept that."
That by itself is huge; the only thing more difficult than gaining a buy-in from a clean start is gaining a buy-in when the person is going to have to change their mind 180 degrees in order to give you it.