What is the best method to make kids learn and grow their thinking capability?

I'm not a teacher but I'm a parent. I think a combination of books, computers, and experience can help kids learn things. Books are great for vocabulary. Today's media like computer and internet offer a wealth of up-to-date sources for learning. Experiential learning can teach kids how to work with groups or solve problems on their own.

I think giving them task to complete (give hints time to time) can help them to develop their thought process quickly. Letting them think, create, discuss can do wonders for them.

All the questions you had mentioned can be used. You just need to check the child's preference of learning because it varies.

There is no 'best method'. This is why the education system is messed up: it's one size fits no one. Each child is different and you have to cater to their strengths and needs if you want to teach them effectively. Offer a variety of methods (my personal favourite is something constructive or creative where they're doing rather than just listening or reading, but again, that's what worked for me and may not be best for everyone) and then focus on those that work best for the child. In a classroom setting, incorporate different methods into the lessons, and then set homework that has options so the child can complete it and learn in the way that's best for them, even if they maybe didn't get to figure things out as much in class.