I promoted these as a trilogy, with a recommendation for readers to start with book one and read them in order. Promo from the publisher that this is a story arc/trilogy is highly important, and the author does the most possible.
!A basic look would be great. (Oh, how I wish At the Edge's cover matched the other two.)
This story arc was my first in mass market, though I'd written 11 Tallchief categories and other author-driven miniseries. Basically, each of those concerned individual stories.
The Aisling Trilogy are individual stories, but with a story line running through that ends with For Her Eyes Only. To plot this trilogy, I used PageFourOutliner, and consider it an absolute necessity. I use it for short stories, to capture critical scenes, to list possible titles and unique character names, let alone to plot. I've tested several programs that would help plot, etc. and found this was the best for me.
The makers of PageFour also provide Character Name Generator and SmartEdit. Good basic tools.
Each story is unique, based on three psychic sisters, so closely linked they cannot live close to each other for long.
The Name Game: Since the Aislings were descended from a Viking chieftain, I chose the names carefully. Heritage, family position, etc. are important in choosing names for characters. Chose the names also, to fit the definition of that name. Baby namer books are great for this. I recommend getting these names down in plotting.
One thing you do not want, is to have a high summit with all characters involved at the last book, and find that there is a Sam and a Samantha, etc.
Character names are extremely important. A tip here is not to match Sam with Shirley, or have the names too close to each other. In romance, the hero's name, opposing the female lead, is important. Typically, the visual impact hits a reader quickly, so alternate longer with shorter for a good match.
Each sister/major player needed certain shared family features, but unique in their presentation and background. I cannot emphasize a character's background enough. This is where fears/conflict/needs, etc. are built. It is also how their lifestyle is reflected.
These families don't just start from zero. Each family has certain traits, certain relatives, so it is important to build a family history, which in this case, goes back to the Viking chieftain and his seer bride. (I like to play in the psychic pool and in producing my backlist for ebooks, I find this thread runs through many of my stories.)
To lay out an extensive plot for all 3 books, each book had a separate plot, with the mystery thread escalating throughout, until For Her Eyes Only, which holds quite a surprise ending. Yet, each book stands alone, the romance resolved--except for the uncertainty provided by the psychic thread.
Book One, At the Edge, is the set-up. It introduces the protagonists, each one's underlying problems/fears/background, and begins the psychic thread that continues to A Stranger's Touch and ends with For Her Eyes Only.
If romantic suspense with a story arc, it's important not to overload Book One with too many facts. Tension has to be built. We're really story-building, after all.
Here's more about the Aislings, psychic triplets....