First off, let's say a little something about structure. There is no one way to do it. However, what's important is that you pick your structure wisely. Structure is not just something that should be fallen into accidentally. It is the scaffolding that holds up your narrative and it should lend to the story in its entirety.
With that in mind, let's start with our first chosen structure:
The three-act structure is a model most commonly used in screenwriting, but also used in novels. It divides a fictional narrative into three parts, often called the Setup, the Confrontation and the Resolution.
SETUP - This is used to set up your setting, characters, initial conflict, and world building. It includes your inciting incident, leading up to your first plot point (where your main character's life changes irrevocably). This is where you need to establish your dramatic question (e.g. Will Emily find her true love, or will the bad guy get her first?)
CONFRONTATION - This is also known as rising action. The idea is for the main character to attempt to overcome the obstacles before them and the antagonist, only to find themselves in ever worsening situations. The main character must learn new skills, as well as arrive at a higher sense of awareness of who they are and what they are capable of. This is vital in order for them to deal with their predicament.
RESOLUTION - This is the denouncement of your tale, including the resolutions of the core plot and the subplots. It is the climax of your novel, and the answer to the dramatic question.
Pros: This structure allows for a plot and character arc that rises with the tension of the novel, and allows for simultaneous, organized and well-set out points that the reader has come to expect and know. It is simple, universally applicable, and many readers expect it.
Cons: This can restrict the creativity of the story and can become a little predictable.
This is where the writer chooses to create a structure of their own choosing - this may involving writing out of chronological order, working with epistolary elements, writing a story in reverse, utilizing tandem structures...anything the writer dreams up.
Non-traditional structure is as wide and varied as the writer's imagination. However, there is a caveat: a strong plot and character arc must still be firmly in place. The reader will still expect to see growth and development of the character, inciting incidents. pinch points, and a solid resolution.
Pros: This structure lends itself very well to suspense, mystery, surprises, twists, and intrigue. It can also be very good for bringing the reader firmly into the character's head if using an epistolary style. Many writers choose this so they can play with the writing boundaries, making a statement with their structure and not just with their words.
Cons: Non-traditional structure can become unwieldy and messy if not handled with care. The writer still needs to engage all the points traditional structure does, without losing the reader along the way. It's also important that this structure isn't used as a gimmick, and that it is used to bring out the very best of your story.
No matter the structure you choose, you must use it wisely. Make sure you use what suits your novel best. Are you working on a thriller? Could a non-chronological novel jazz things up and lend to the intrigue? Could an epistolary novel of letters and diary excerpts add depth to a romance novel? Or are you on a hero's quest that works best with a traditional structure, or a sci-fi novel that demands a clean three act format? That's not to say certain genres need one format or another. Certainly not. What it does mean is that you need to think through your structures and decide which one makes your novel better, stronger, and clearer.
At the end of the day, it's your choice - but choose wisely.