I was chilling in the sun with a pigeon and a rabbit when I thought about this article

No one is for taxation in and of itself

People who advocate for taxation aren't actually for taxation, they aren't even for everything that is funded by taxes. What they are for, is some of the things that are funded by taxes. And what exactly it is they want funding for? It differs from person to person. They have never thought about how things could be funded, they just feel it's important that it gets funded because they value what the politicians promised to deliver. They have been told that taxes is how it is and has to be funded, they never questioned that.

Hitting people in the head with taxation is theft! 

So when someone asks them to justify theft, they don't want to. They want to defend the funding of things they value. They don't want to think about the fact that it is being done in an immoral way. Hense they prefer the euphemisms like taxes to avoid cognitive dissonance. When you describe something reprehensible as something nice or neutral it doesn't sound that bad, you can pretend like you're advocating good things and feel like a good person.

Don't make them defensive!

When people become defensive, arguments are usually without effect. They see you as the enemy and assume you are of ill intent. Obviously, you hate education, you only want rich people to get healthcare, You hate safety and cooperation, you kill poor people for shits and giggles, you pray for a world without roads so nobody can get anywhere, basically, you're a selfish, evil, stupid, lying bastard! They don't want to be convinced, all they want is to defeat you.
When you change your mind, a little piece of you dies and a little piece of you is born. This, just like any change, can be very painful for a lot of people.

Finding common ground

So if you want to convince people that cooperation and voluntary interactions are preferable to violence and coercive authority, it helps if you start by trying to find some common ground. Maybe start by asking if they value safety, education, helping the poor, having access to health care or protecting minorities. I'm just speculating now but I think most people will answer in the affirmative. I also suspect that you value these things, at least you're not opposed to them in and of themselves, right?

Don't start by tearing everything down!    

Think of it this way, if you're trying to convince someone to hire you to build them a house, you don't start by blowing their current house up. So don't start the conversation by stating your end goal, abolish all government! It's going to be perceived like, let's blow your house up! If you're an anarcho-capitalist or voluntaryist you have spent some, or more likely a lot of time thinking about how things could work without governments. You know a lot about how ineffective governments are. You know that when a central banker says that there will be no more financial crisis in our lifetime, prepare for an imminent financial crisis. The person you're talking to hasn't spent all that time thinking about this stuff. They will most likely fall back on what they've been told to believe without questioning it.

Okay, I get it, don't tear everything down, so tell me what I should do!

Well, my suggestion is that after finding common ground, you ask them for example if they think that the Swedish government would get more tax revenue if they lowered the taxes seeing as the Laffer curve dictates that people are incentivized to work less the closer you get to 100% tax on income and the Swedish taxes are higher tan the "sweet spot" for maximum confiscation thru taxes. Not because you want the government to get more tax revenue, but because you're getting the other person to think about it, you're planting a seed, not convincing them to agree on everything. Then maybe offer them some resources to read something about Austrian Economics or something.

Thanks for reading, let me know what you think, am I making any sense? If you liked this maybe you will find some value in my previous article about letting go of possessions.

For more on philosophical, psychological, and economic perspectives on morals, politics, law, and other topics give some love to @morality2, follow and check out his latest article. War, taxation, and ultimately government itself will eventually go the same way as slavery and human sacrifice