So writers, where are you in your work in progress? It's a question to ask yourself often--and I don't just mean, how far along are you in your draft? Also, do you know exactly when and where each scene takes place, and have you told the reader?
Chapter Nine of Briars and Black Hellebore opens three miles and a hundred years from where I started the book, and every character that appears in Chapter Nine is completely new to the reader. When I brought Chapter Nine to my writing group, it opened with a scene of a monster guy sitting at a table crying as he counted spoons. A handful of people wandered about in strange attire making snarky comments at each other.
Of course, my reading group was a bit disoriented and confused about what was going on--and who, and when, and why. In a first draft, it's easy to forget to orient the reader in time, space, perspective, and mood. (Also, sometimes, in key plot points.) But it is essential to keeping the reader's attention and can be done briefly and simply.
I added the following paragraph to give just enough information to let the reader get her bearings:
Gustav peered through his hairy claws out of the slim, peaked window that framed the ruin of Old Vepres-Castle on its hilltop three miles away. The dragon that had lived there for nearly a hundred years stretched a translucent wing skyward, from its nest atop the West Tower. The scene was hazy to Gustav’s poor eyes; the ruin was an oily blot on the clean, snowy landscape.
Now the reader knows exactly where Gustav is (three miles away from where my story originated), that he has "hairy claws" (combined with other details in the chapter, indicating that he is the "Beast King" discussed previously in the story), and that nearby there is a dragon "that had lived there for nearly a hundred years" seen in a "snowy landscape" (so we know it is about one century later, in the winter).
My goal is to give just enough information in this paragraph to orient the reader and also start to build a little suspense. The reader can now deduce that the hundred-year curse upon Old Vepres-Castle is almost at its end.
J.K. Rowling is a great example of an author who does a great job of orienting her reader, particularly in the Harry Potter series. She's like a GPS system, always letting the reader know exactly when and where each new scene takes place. It's especially important to do this in books written for younger readers, but it makes writing for adults easier to read as well. And it makes editing and timeline adjusting a heck of a lot easier for the writer, too.
Check out the blog How to Write a Book Now for concise, practical advice on this and other book writing issues. The other fantasy writer in my group also talked with me about how, even though it feels super dorky, it can be enormously helpful to create a written out timeline (in addition to an outline) and a physical map of the story's time sequence and location. When you as the reader have a clear grasp on "where you are" in the story, it's much easier to lead the reader through the story at just the right pace.