You have to have a core idea that can be sustained over three books – take your vision expand on it, add characters, create a lush story. Take the kernel of story from the first book and developing it more fully.
Drawbacks – it’s not the right time or the write story. Stretching the story makes it thin.
An ongoing series is much bigger than a single book – more work. You tend to see diminishing sales returns – not everyone buys into the trilogy- Every time a new book. Comes out, you may see a sales bump to book one. You can throw a lot of different scenarios and tweak characters in a series
More complex story arcs fit a longer period of time – duopolies, trilogies – because the events and character development can’t be compressed into a shorter period of time. Can spend more time on setting.
– You actually have to live with your characters for a long time – you can get to dislike them
Agent may or not buy into the trilogy. If they don’t, then that’s the end. Will Marketing be able to deal with the book if it straddles several genres? Benefit of a smaller press – they maybe more willing to take a risk on the series.
Be aware that if the subsequent books are not bought, you have to tie up the loose ends in some way.
WRITING IS LIKE DRIVING ON A DARK HIGHWAY AT NIGHT.
– Do you have an end in mind or is each book open ended?
– Be open to characters you didn’t expect showing up in subsequent novels
YOU MAY BE GOING TO SAVE THE WORLD, BUT YOU HAVE TO BE ON TIME FOR THE DRESS REHEARSAL.
Be ready to pull out chunks of story that don’t work….
Research your locations to enhance believability and reality – add local colour. What events are on, what’s the weather like, which sports teams are playing, concerts, etc. Put a spin based on the flavour you’re aiming for.
Figure out how the world you’ve created works – government structure, water, food, transportation, education.
Search for World-Building on the Internet or check resources such as One Stop for Writers.