They are eager to try new things. They are eager to experiment and see what happens when they attempt a new tactic. If it doesn't work, they don't give up. They keep going at it until they get an answer. This is the mentality that adults need to have.
Children have minds like sponges, and they keep adding new things to their mind regularly.
They don't give up when things get them down. Notice how the child reacts when things don't go right. You'll probably find a level of persistence and creativity that will astound you. Learn from those little professors. They can teach you a lot.