It is widely accepted that creativity is essential for a fulfilled life. I would say the first step to think creatively is opening your mind to a different reality, to different possibilities. We all have an inner child that wants to play and experiment all the time, so embrace it. If you always look for the logical explanation and take things for granted it'll be harder to be original.
The next step is questioning everything that catches your attention. How did this happen? Why did it happen? Why didn't it happen in a different way? Trying to find answers will stimulate new thoughts. Some of the great things of today were based on ideological revolutions but they happened because people also fought hard for them.