Having parts is a good thing. Dawn of the Epoch was a four part book. In the first part, the story started. The second part was mostly exposition. It set up the story. The third and fourth parts were much longer. The third part contained the buildup and climax of the action. The fourth part contained a resolution of what happened in the third part. It also contained another build up and decline in the action, but with a slightly different objective.
Exposition means “the act of expounding, setting forth, or explaining.” (Source: Dictionary.com). Exposition is where you set up the story. If the story is complicated or if it is fantasy or sci fi then you might need lots of exposition. Here’s the catch: No one likes reading exposition. It is like reading a textbook. There is too much learning involved. Book reviewers love to say things like, “Well, the story was good, but it had too much exposition.” You cannot ever totally avoid exposition. To some extent, you need it. What you can try to do, though, is weave the exposition into the story rather than giving readers large doses of it at a time. If you are writing large blocks of narrative text, then ask yourself if you can break it up somehow. Have the characters talk their way through a scene, instead of you telling the reader what happens. Alternatively, try switching from one character’s perspective to another. Get creative! Do whatever you can to avoid those onerous big blocks of narrative exposition.
On the other hand, I have read books on Wattpad that are woefully lacking in exposition. I have read books where characters are doing things and talking to each other, but I have no clue why they are doing what they are doing or who they are. Your readers need context; they just don’t want to be buried in it. You have to perform a balancing test and make judgment calls. Just make sure that you are thinking about the balancing act as you write. Don’t get too caught up in the moment and ignore the need for balance altogether.
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Most stories follow a typical narrative style: Introduction/exposition—building tension/anticipation—climax—denouement/resolution. For a detailed explanation of these things see this Wikipedia article - http://en.wikipedia.org/wiki/Denouement#D.C3.A9nouement.2C_resolution.2C_or_catastrophe/. I would recommend not deviating from this pre-set formula. Once you are a master, then you might try to do something avant-garde and it might be sublime. First, however, try to do the basics well.
Let me give some advice about the first part of your story. I have read the beginning of a lot of stories on Wattpad. I hate it when I am ten chapters into a story and I still have no idea what it is about. If I don’t have a clue what the story is about, then I don’t really want to keep reading it. If the story is a biography of a character, then let me know. If it is about overcoming an obstacle, then drop me a hint. If it is about the outbreak of a new plague, then who will try to stop it and how will they try? Is a villain going to emerge? Don’t give away critical details, but do give some indication to the reader of what goodies are in store if he keeps reading. Don’t say things like, “just wait for the next couple of chapters, that’s when it really gets good.” How do I know I can trust you? I’ve never met you. Instead, say something like, “Throughout the months to come, the knight’s commitment to his family would be tested by the horrors of the imminent war.” Now I know that the story is about whether or not he will stay committed in the face of atrocities. The great thing about a good outline is that it allows you to confidently drop these tantalizing nuggets that leave the reader salivating.
Your characters might do interesting things and meet interesting people, but if all of that is not tied together by an overarching story with tension and relief built into it, then it isn’t particularly fun to read unless it is some sort of academically brilliant gem. Even if book snobs rave about it, however, it might not do well on Wattpad. I think most Wattpad readers want to be entertained, not edified.
In Dawn of the Epoch, the first and second parts laid out the story. The third part was the story. The fourth part was the grand climax and finale. I had outlined out what would happen in each part in my overarching narrative, but I did not outline each part until I came to it. By the time I made it to the fourth part, I was incredibly eager to begin.
It feels good to finish a part, really good. The sense of accomplishment that you feel when you finish a chapter is magnified by ten when you finish a part. Therefore, I recommend breaking your book up into parts. Having four or five parts is good: Either (1) introduction, (2) build up, (3) climax, and (4) wind down or (1) introduction, (2) build up, (3) climax, (4) struggle, (5) resolution. Both of those structures are good. Also, in order to write a complex, full-length book, you need intermediate stages of outlining between the big one and the one that you will do for each chapter. I found that concentrating my energy on one part at a time helped me stay focused. It kept my mind from wandering. It is easy to worry about what will happen to your characters after the big climax, but until the climax happens, you should keep your focus on what is happening to them right now.