Down From the Door Where It Began

Could you spend a few sentences on the topic of first chapters? We hear a lot about throwing out the non-happening first chapters of the draft and starting where the action starts, but I'm hoping you can elaborate a little more on elements you feel like really need to be there for a first chapter to work. Character, action, backstory, etc. all have to be balanced properly, and while I don't believe there is a formula (or that you should write to one), I think there ARE things that just have to be there.

You're right about there not being a formula. Character, action, backstory... the balance between them has to vary for different books.

In terms of what must be in a first chapter, you're almost there already. The thing that should be in every first chapter is what makes the story worth reading. (Not necessarily what makes the story satisfying, in the end; not necessarily what the story is about.) What makes the journey worth taking.

Lots of writers write a first-draft first chapter that is, really, them orienting themselves in the story; the writer is packing the bags she'll need as she plays tour guide on this trip. Start your story after that part--start your story not where your journey into the story starts, but where the reader's journey into the story is ready to begin--the baggage and gear are for you, not your reader. A good first chapter is not the packing for the trip part; it is the setting off. A good first chapter allows the reader to begin their journey just as Bilbo Baggins did-- without luggage or map, but with the road before him, and a wide vista beyond.