Make a list of 5 elements you know you want in your next story (or book).  If you know what tone you want, a few of your main characters’ traits, whether you want first or third person narration, what genre you want, where you want to set it or what kind of setting you’d like to use.  For example:

1. three friends as the central characters
2. lots of humor and banter in the narration and dialogue
3. scenic setting…maybe on a journey of some kind?
4. adventures and mishaps, and maybe a battle with a tin of pineapple?
5. a dog

And that example is pulled from Three Men in a Boat (To Say Nothing of the Dog) by Jerome K. Jerome, by the way, which is the funniest thing ever written.

Think of it as sort of a wish list for your story.  List more than 5 things…list as many things as you can come up with.  Fill in the details.  You want to write something that will fit into the steampunk genre?  Okay, so which established elements of steampunk do you want, and how is your story a little different?  How can you take an element of it a little further, give it a twist, or focus on an area that’s been overlooked before?  You want an exotic setting.  Otherworld or real-world exotic?  If it’s the real world, pick a place you’ve always wanted to know more about, or that you’ve visited, and do some research.  If it’s otherworldly, are you going for futuristic, alternate history, another planet, science fiction, or fantasy?

The point is to aim for what you’re excited about writing, and then get you asking and answering questions to focus your sights.