Ever seen a child create something? They sing, they dance, they tell stories, they explore, they build and they create. It's an uninhibited way of trusting in one's own capacity and imagination, letting this come to fruition, seeing endless possibilities. This is the source of creativity.
Our way of being creative is wide and free, until we start school, where we gradually become more aware of what others think of us and that we want to fit in. Our societal conditioning begins. To unlock this creative force, we must tune back into our inner selves, the way we were when we were little. For some of us, our upbringing might have been traumatic, but before that, is an innocent child. To reclaim him or her, we can rebel against our parents by using our creativity, whether for pure art or commercial projects. Our anger, sadness and frustration can become our fuel, rather than create anxiety. Or be a way to deal with anxiety. This is what I learned during my education to become a copywriter in the 90's and have applied on myself ever since. I have for example noticed that I'm a better writer, when my emotions are welling up more.
So, want to be more creative? Want to express yourself more uniquely? Reconnect with your inner child, and let his or her eyes lead you back into, how to look at the world.