I have a rich background in fantasy, science fiction, and urban fantasy honed by years of reading great books and... comicbooks Actually, comicbooks (like Plume, the Legion of Superheroes, or even Sandman) were pretty formative.
It's normal for comicbook stories to span several issues, and that's important for writers to learn. With arcs sometimes ending a year or more out (like a TV show), while reading them I learned to plant seeds in one story that would ripen for harvest in future books.
As a Discovery writer, this has become so standard a practice to me that I do this on the fly. I discovered that I could trust this process (and myself) while writing fanfiction, and it is critical to all of my series. If you've enjoyed any of my work, you know that loose ends may crop up in later books with delightful effect.
If you're a writer, here are some tips on how to master this skill. And if you're a reader who's loved plugging the hints in during a big reveal? Here's how I'm story writing with hints!
1. Do some light foreshadowing:
While you're writing, don't fight incorporating seemingly inconsequential details into your plot that gain significance later -- in later books, for example. The casual mention of a mysterious character, an artifact, or a prophecy can set the stage for major future developments.
2. In the real world, there are unresolved mysteries:
Leave some questions unanswered. I learned this from a major writer who shall not be named, whose books wrapped everything up in a bow. Everything. But a mystery that lingers at the end of your book can be a compelling hook for the next installment.
3. Character development can take entire books -- don't phone it in:
Introduce characters that have untapped potential and don't explain everything about them with page after page of information -- something called a 'story dump'. These 'dumps' cheat the reader out of the excitement of revelations and growth, and cheating the reader is a No-No. Remember, the actions of characters in the plot should determine their characteristics and how much a reader needs to know about them. Often, hints work better than facts. Let the reader savour payouts.
4. Characters know the world better than the reader and can drop hints:
Characters can hint at the broader world beyond your current story's scope. They can mention unexplored lands, unmet societies, or unknown cultures and problems, and it will create the sense of a larger universe waiting to be discovered. This can create menace and anticipation for the readers, which makes for a rewarding read.
5. Themes can span books and series:
You can write themes into your work that extend across the series. For instance, if your current book explores the theme of trust, the next could delve into broken trust or betrayal, which can creat a thematic continuity. But these themes don't have to be cerebral (like growth or recovery). Winter. Snow. Privation. A town can become a theme that links books in a series together. When I've done this successfully, I've found out the destruction of such an object can surprise me with its emotional impact on readers. Tread carefully. Mke it rewarding for them.
6. Real emotions make for a real journey between books:
Begin emotional journeys that take time to resolve. A character's quest for redemption, or search for identity, or struggle with internal conflicts can span multiple books. The number one tip here is that the emotions must be real. If they are 'fake' or designed to suit the plot despite the established character, you've short-changed the reader. Don't do that.
7. Symbolic elements can create ties:
Symbols or motifs that can be revisited and even reinterpreted in subsequent books. This is an easy way to create a thread that ties a series together. This can be anything from a book to a button. Symbols can have a lot of impact.
8. Remember your cliffhangers can connect a series:
They're not always necessary, but a well-placed cliffhanger can be an effective way to lead into the next book. Make sure it’s interesting but doesn't leave your current story feeling incomplete.
9. Crafting a legacy also works:
Introduce elements that hint at a larger legacy or destiny for certain characters. If you do this right, it sets the stage for even epic developments in future books. The better you do this, by the way, the bigger the reveal when you get to that point. In fact, sometimes readers have become so used to writing that's 'going through the motions' that the revelation and sudden payouts falling into place can make them gasp with delight. Learn to hint about a legacy.
10. Balance is key:
While you're dropping your hints, make sure the integrity of your current story is maintained. The characters must give readers reasons to care about them, for example. Nothing you're hinting changes the stakes for the current story. Ensure that hints enhance rather than detract from the story you're writing.
Do writers do all this things perfectly? No. But an honest effort can't be faulted and you will get better at them with time and practice.
Finally, the goal is to create ties that bind between books and series. A seamless transition can excite and intrigue your readers, and compel them to continue the journey with you into the next book or a related series, so while you're learning, don't give up. And if it's tough, tough it out! Try, try again! And, as always, happy writing!