This is quite a though question.
As personal traits there are several things that I would seek to boost - curiosity, rationality and kindness above all.
Also I surely have a specific curriculum that I would like my children to go through, beside what is thaught in school and the findings of their natural curiousity, wtih the important note that I won't be pushing them for some super achivements in these, just to learn the basics - for serious development in these or any other area is a choice that the children must do on their own.
These are:

• to ride a bike
• to play a music instrument
• to learn some balroom dancing
• to get some martial art practice
• to learn a traditional weapon (some kind of fencing, archery, etc)

I believe these help to build a specific mind setup and streghten confidence and selfesteem - things that a very important for a person to be successful.

Answer all their questions honestly, and if you dont' know the answer, help them learn the answer with you.

Teach them the fine art of questioning everything. If they make a blanket statement, help them to dissect why they did so. If someone else does so in the presence of your child, ask questions to determine why the person arrived at the conclusion they did, right or wrong. Let your child see critical thinking in action.

I'm no expert, but I suspect that questioning is the cornerstone of thinking, and in my limited experience, kids question everything.

I think they have to be taught (raised) to 'not question'.

I'm not sure if that answers the question or not.

Provide resources, opportunity, guidance, responsibility with accountability, patience, and a good example.

How does one not raise them to think for themselves?

I taught my kids to be who they want to be. My 22 year old dropped out of high school in her senior year and believes in conspiracy theories. Hope its just a phase. lol

As a new daddy I'd love to pin this topic. My goal is to help my son become who he wants to be.
I look forward to reading others' thoughts.

First and foremost, you model the behavior. And, you ask a lot of questions wich get them to think about lissues and behaviors.

We have raised our grandson since age 8. He is now 14. He is not afraid to question authority or to confront incorrect information. As a result one of his teachers who is at odds with him on religious and political issues is afraid of him. Even at his young age, he has formidable debate skills far exceeding mine. Frankly, I am a little afraid of him too. But I am still stronger than he is, so I have that going for me. For how much longer, I do not know. I have no idea how we did it. We also raised his mother, who made every wrong decision an adult can make, and his aunt, who is very insecure despite being amazingly talented and smart. He says he wants to become a doctor. I think he can do that if he wants to.

Is a lot of work. You have to pay attention to them and constantly adjust your behaviour to lead them in the direction you want them to grow. You have to adjust becuse they can't. They can't adjust becuse they're children. You have to understand their wants, needs, and abalities. You have to give them the intillectual and emotional tools for them to develope their abalities and fulfill their needs. You need to teach them to walk the line between being a pushover and being a bully. You need to treat them with the respect that you want them to treat you. You have to walk the line between being laissez faire and being an authoritarian. And this is just for starters.

One thing I would do in this modern world is to make sure they are spending some time away from their phone, computer and any other such devices. In order to experience real life and learn to solve problems with their hands and hearts, have them learn to cook something, take them camping, grow some plants outdoors, help them build a birdhouse.

Be a decent human being. Think for yourself. Don't take it to seriously.
Also if you do raise a self thinker be careful becaise that can bite you in the *ss for awhile when they hit middle school or so. No joke grow a thick skin

I am, seriously, the last person on this planet to answer this question.

But I'll give it a shot.

Treat them like an adult. Look them in the eye, watch for their response and react to that. In my (limited) experience, they do not like to be patronised. And good for them.

So, that's how I mess up the children of my friends, but it generally seems to work. As far as I can tell, no one got hurt and there was no property damage.

My parents didn't do much right but one of the things they did do right was instil in me the habit of doing research when I wanted to know something. 'Go look it up' might sound dismissive to a kid asking the usual kid questions, but nowadays I'm glad they said it. So I'd recommend doing that. Granted, these days you have to be careful about the answers you get, so I'd teach them that, too. Always verify.

Set a good example. Set boundaries and set reasonable and consistent consequences for crossing those boundaries. Set the expectations of escalating consequences if boundaries are crossed repeatedly. Praise good behavior immediately and clearly. It doesn't have to be a celebration, but clear acknowledgment and appreciation reinforce the good stuff.

That's a good start.

Throw things at them and see if they can catch them.
I never lied to my kids when they asked me a question, I did what I could to teach them as much as I could. I did not rely on the school system.
I would play games with them, tell them untruths which gradually became more and more unbelievable. Then they would start to catch on quicker and quicker. I hope they learned not everything people tell them is true.
I always tell young people.
Observe independently
Judge critically
and take inventive risks.

I try to have honest conversations with my kids. Even at a young age they get ideas from peers who are brainwashed by their parents.