Both! I don’t think you can separate these. It’s like asking whether you need water or oxygen. A strong character will not only drive a plot, he/she/it can create one (awkward characters create problems for themselves as well as for others) but that person needs to have something to aim for or escape. A story where there’s no conflict, where there’s nothing to be resolved is no story at all.
A strong character in a weak plot will stand out but only to show up the plot’s weakness. A good plot with weak characters will be disappointing. You need your cast to be able to act the part. But get the characters and plot right, strong, memorable, and the story should zip along and be a wonderful read. When reading other authors’ works, I recall their strong characters and their plots.
When thinking about a character, what do you focus on - physical attributes or personality traits - to flesh that character out?
I focus on personality traits. In Eileen’s case I knew she’d be as awkward as they come, often to her own detriment, but she would also be brave, honourable and prepared to make considerable sacrifices for causes she considers worthy enough. So being prepared to give up what the Queen considered a privileged lifestyle for a much more humble life on Earth with a mere human male is something someone like Eileen would do without that many qualms.
I have since fleshed Eileen out physically with chestnut hair, a good figure and great skin. But I do think the physical attributes are less important (though Eileen has been known to use her physical wiles to help her cause, especially when she was living in the Kingdom). Had I been stuck for physical attributes, one good idea often repeated in writing circles is to take photos from magazines and so on and “blend” different features from pictures you like to create your heroine.
I’ve found it helpful to “see” my heroine in action, doing things, speaking (and getting a good idea of her voice did help give me her class and as a result ideas as to what she’d look like – she’d be unlikely to be a blonde bimbo) and from that other aspects of Eileen’s life, including her looks, fall into place.
Who is your favourite character in your works? Why?
Eileen as she is brave, hardworking, knows the value of true love without being soppy about it (she’s one of the least soppy female characters I can think of), is prepared to make sacrifices for her loved ones and fights evil. She’s not afraid to stand up to the powerful Fairy Queen, her cousin.
Eileen is not fazed by wealth or power nor does she seek either for herself particularly - she just wants enough of both to get by and to ensure people don’t go out of their way to give her grief on the very good grounds they’ll get it back with considerable interest.