Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Energetic Yet Ominous
Remember show and tell? Basically, you'd bring in something interesting/weird/gross and talk to your classmates about it. Authors like to apply those same rules to writing. Instead of telling us something ("Jamie is excited"), they show us instead. O'Roark Dowell is queen of this. She doesn't come right out and tell us how Jamie is feeling, but slyly uses the tone to do the talking. Take a look at this passage:
TJ's next so-called letter came two weeks later. I ripped open the padded envelope, hoping this time there'd be a note with some real news in it, some good old-fashioned descriptions of rifle reports or a hand grenade rolling across a jungle path, something that would give me a real feel for what it was like to be TJ right then. It might be tough for me to actually get a job as an ambulance driver in Vietnam, but if TJ would just write me a real letter, it would be like I was there in Vietnam, right beside him. (7.1)
What do you feel when reading that? Excited, eager, enthusiastic, and maybe even a little scared, right? (That's what we felt at least.) The tone of Shooting the Moon helps us figure out what's going on with Jamie, and how we should feel about it. Often, there's a very energetic tone, like Jamie is going to explode if she has to wait one more second to share her story with us.
Underneath that, there's a sense of danger lurking in the distance. It feels like something terrible could come out from under the bed at any moment and scare us. We know that TJ is at war; we know Jamie adores TJ; and we know that war is much more complicated than Jamie realizes. Again and again, the tone hints that something bad is about to happen. Just. Around. The. Corner.