My novel Chasing Forever Down is set in the fictional surf town of Crescent Cove, California. (Can you guess what C will be tomorrow?) The story is set in the early part of summer, and as you've probably guessed, there are tons of beach scenes! Regardless of what happens in my novels - drama, conflict, fun, romance, etc. - I try to keep a consistent vibe or mood for the story. With CFD, I wanted a laid back beach vacation feel. Even if there's action and insanity on the pages, when my reader finishes that last page and looks up from the book, I want them to feel like they've spent the last few hours/days sitting on a beach towel in the sand surrounded by palm trees and salty ocean waves.
I try to take a major element/theme from the book and apply it to the overall vibe or mood of the book. Do you aim for a certain mood for your books? Do you allow your reader's mood to change with the MC's mood? With the plot changes? (Or as a reader, what do you prefer?)