Perhaps you have already written some books, perhaps you are just starting, or perhaps you are just considering it. Regardless, I feel that you will get your creative process from one of three places: The brain, the heart or the gut. Here is how I see it:
Those who write from "the brain" are using logical thinking and would primarily be writing nonfiction, manuals, textbooks, etc.
Those who write from "the heart" are using their love for something or someone to motivate them and their creative thoughts stem from that. Perhaps you are "in love" with being "in love". Lots of romances are written this way. Or, if you have a genre or a hobby/interest that you are passionate about, this might lead you to write from the heart. Someone who has experienced a death, abuse, losing someone violently could also write from the heart.
Writing from "the gut" is where you have an idea for a story and it just "feels right". You know inside that the story should be told, don't have a clue how it is going to develop, but trust your instincts to just get it down in words and go with it.
I happen to get a gut writer. I have always believed that your gut will never let you down or lie to you. Your brain defines something by past experience or knowledge, your heart defines something by how you want it to be or feel it should have been, while your gut defines something by how it IS for you, how you deep inside know who you are and what you want to say.
In regard to fiction, many people say to write from your heart. There is absolutely nothing wrong with that, but I say write from your gut, if you can.
That comes out true and gritty, with a part of your soul and essence inbedded in the story. To me, that will make your characters real and the story believable, no matter how far out you go. It IS ficiton after, all!
Feel that hard push deep in your gut, open yourself to the momentum from the push, and start putting words down. Pretty soon your story will take shape. You will then be traveling down roads you never even imagined.