How much liberty are we allowed in creating a new place in our settings? I have a 3rd book of a series set in a town in California. My opening scene takes place in a park, but I can't find a park in the town that's like the one in my head. Can I make one up entirely or can I use an existing park and "plant" some trees or a place for an outdoor concert?
Camy here: It's fiction. The sky's the limit! Create new places with impunity!
Now, since you're using a real town, don't call your fictional park the same name as a real park in the town. Make up a name so your readers—if they're familiar with the real California town the book is set in—won't get jarred out of the "fictional dream" of the novel to say, "Hey, that's not in XYZ park. This person didn't do her research!"
If your setting—whether a house, park, building, or entire city—is fictional, make it obvious to your readers that it's fictional. Don't name it something too similar to what really exists.
If your setting is a real place, be meticulous with your research. There are people who live or have visited that real place, and if they spot inconsistencies or errors, they'll be knocked out of the story. And you want to keep them reading, not make them wonder if the town square really has a statue of General Jackson or if it's really President Lincoln.
This is especially true if you're writing a historical novel. If your town/place is fictional, make it obvious it's made up. If it's real, be exact on details. Historical readers, especially, pick up on that kind of stuff.
Also, don't forget that your setting should be a character in the book, not just a backdrop. When you integrate the setting into the storyline—so much so that the story couldn't take place anywhere else in the world—it makes for more vibrant reading.
If you have any other questions for my Q&A series, just leave a comment and I'll be sure to get to it!