Imagine you want to do something but are around people who don't really want to do that thing or are indifferent enough not to try to do that thing. It could be going to a restaurant nobody else particularly loves or watching a movie that may not be the thing everyone else wants to see or buying something when your partner is against it. For this to work, they can't be too against it, just either indifferent or mildly against it. Otherwise all of this fails and you end up in a fight. (People who are really good at passive aggression will poke and prod to determine how far they can go, and then use advanced tactics, which I can write about later on if needed, to manipulate people so that they'll go further.)
Step 1: Present the problem related to what you want early on.
By stating the problem, you can imply that they must solve the problem. Remember that in passive-aggression, it's important that you keep all of the focus on everyone but yourself. Additionally, you want to put the issue at the feet of the other people as soon as possible. That way in follow-up presentations of the problem you can reinforce that it is their problem to solve.
Let's say you want to go to a restaurant that your significant other doesn't like. It's best to be the one who says "what are we doing for dinner" first, so that your partner will be the one who has to answer the question. I've been in situations where people ask "what are we doing for dinner on Friday" and it is Monday, and by being that early the person can, day after day, ask the question again, which solidly re-enforces that it is my problem to solve.
Step 2: Knock down other suggestions through vague disappointment.
You want to be careful in how you dismiss other people's points, as you want to keep the attention on them. Remember that you want to keep the responsibility to solve the problem on their end, that way you have full control over whether they succeed or fail. The best way is to show vague disappointment. Make it sound like every word anyone else says that's not what you want is something they said that's clearly incorrect and you have to be a parent standing there shaking your head.
So, in the dinner example, say things like "I mean, if we have to eat somewhere, and that's probably edible," if you need a longer thing to say. But often it is best to say "I guess" in a sad way or the classic "oh, I don't know." Sometimes you have to say "oh, I'm not feeling like eating something like that tonight" to things that are unarguably valid eatery choices that aren't the one you want.
Step 3: Eventually people are going to ask you what you want. Deny having an immediate opinion.
It's important not to immediately state what you want, otherwise you will be caught in your act of manipulating people. Instead, feign ignorance, implicitly accepting that the solution is a difficult one. Sometimes when you do this, you'll have to further dismiss the other choices so that the other people don't conclude that you are for one of their choices as it being a sub-optimal but only reasonable choice.
So for the dinner example, if they say "Do you have any ideas, then?" you could then answer "Not yet, but I'm thinking" emphasizing the word "thinking" to imply that this is a tough decision (though you already know where you want to eat).
Step 4: Once the other people make one more suggestion, immediately ignore that suggestion and add the one you wanted.
Here you want to show that you all-of-a-sudden had a great idea and that by ignoring theirs you have implicitly suggested that their last-ditch idea is not worthy of considering. Typically you want a sentence to show how your idea solves the problem but theirs does not. Or you just say "clearly the best choice" or something like that to indicate that it was an obvious choice from the get-go once you paid any mind to the problem.
Step 5: If the other people balk, increase the responsibility and intensify the focus of the decision-making on the other people.
A good amount of the time, the other people will say yes by this point. But they may not. And if they don't, your job is to use that work you did to re-enforce that it is their responsibility to make the decision to force them to make your choice. Often this is done by presenting the question again, but more seriously (careful not to be too forceful so that they don't question that it is their responsibility). Now they are stuck in a bind. They can either do your choice, which is clearly going to make things go smoothly for everyone, or raise the stakes and possibly get into an argument. This is where you win.
So in the dinner example, if they say something like "I'm not sure about that one…", indicating that they don't want to go to your place of choice, you would then have to say "yeah, but we need to make a decision on where to eat." Look at the other person when you say "we" to imply that you mean them.
Step 6: If there is any further balking, play the victim.
Most of the time, you will already have gotten what you want. But if they persist, then you need to play the victim of their failed responsibility to make a decision. You have to make them feel like they'd be a total asshole not to just do whatever it is that you say. You may lose in some of these cases, but you'll have a lot of credit in your loss as you now made the other people believe that they've done something bad to you and so in the future you can constantly bring up this wrong decision as leverage to get what you want later on.
"I'm really hungry, can we just go to [place you want to eat]?" is a good suggestion of a sentence to say in our dinner example. You've now overdramatized yourself as dying of hunger and are implicitly suggesting that they are a total asshole if they don't resolve the problem through your choice implicitly designated as obvious. If you don't get the place of your choice in the end, constantly talk about that incident and how your partner forced you to have a bad time there as leverage.
Step 7: If you succeed, ask for feedback.
In the vast majority of cases, people will elect your choice. When this happens, always try to ask for feedback later on, as it is always to your benefit. If they end up not liking your choice or if you ultimately don't like your choice, remind them that it was their decision and their fault. If they end up liking the choice, remind them that it was your suggestion. In both cases, you now have additional leverage to get what you want.
Why use this approach? Why not ask the person/people directly?
Asking people directly can lead to conversations where you don't get what you want most of the time. Passive-aggression allows you to tilt the scales through manipulation so that you get what you want with a far higher rate of frequency.
Also, if you do this often enough, people will begin to cave and do anything you say. And you'll get what you want even more frequently.
Can I use this against other passive-aggressive people?
Yes, but you have to be careful. They're going to try to re-direct responsibility to you and so you'll have to work harder to re-enforce that it is their choice. Often it is a good idea to continually remind yourself of every thing the other person has ever done so that you can implicitly suggest to them that this decision is punishment for their misdeeds in the past. Or suggest that you did a majority of the responsibilities in the past (it is best to over-exaggerate here) and so it is one of their many turns to have the burden of making the choice.
What if they say the dreaded line "I don't know, what do you want?"
"I asked first" is an appropriate response (hence why you need to ask early!). Or bring up a time when you did make a decision and then say it is their turn. Or just say "I don't know." Or suggest that they are being aggressive and that it's harmful to you so that they feel even more power to do what you want. Whatever you do, don't just straight-up say what you want because that will lead to them being on even footing with you (or worse) and you have less of a chance of getting what you want.
Hello, I am someone who wandered into ULPT accidentally. I'm don't want to do this, but I am a victim of this happening to me. What can I do?
In my experience, there is no way around this sort of passive-aggression. If someone is using this technique against you, they will get their way a large percentage of the time. This is why it is such a powerful technique.