HEROIC. Characters in fiction – and especially in romance – need to be heroic. I don't mean heroic in the sense of wearing a cape and tights; I'm talking about heroic in the sense the word was used in classical literature. People in fiction are in some way larger than life. They're more than real people. Their problems are bigger or more intense. Their flaws are more problematic, more likely to lead to huge trouble. Their personalities are brighter, or darker, or richer, or more twisted, than those of ordinary people. In this view, even a villain is a heroic character -- because he's not simply a guy who commits random, casual crimes. He has a plan and a purpose and a motive.
EXTRAORDINARY. Think extraordinary, not perfect. In the work of new writers, I see a lot of characters who have it all. They’re gorgeous. They have great jobs. They love what they do. They have wonderful friends. They live in a great house or condo. They drive the car they've always dreamed of. They have designer clothes and shoes and hair. But the thing is, people in books are much more intriguing when things aren’t going right for them – when they’ve lost the job or the condo or the friend.
BALANCED. Characters work best when there's a basic balance between the protagonist and the antagonist (or, in romance, between the hero and the heroine). If you build a big blustery hero who always says what he thinks, and you pair him with a heroine who’s got low self-esteem – the hero comes off as a bully and the heroine as a weakling. If you pair a soft-spoken laid back hero with a hard-driving, bossy heroine, then he’s apt to look weak and she may come across as being bitchy. But if you put the blustery hero who always says what he thinks with the heroine who’s just as outspoken and bossy, you’ve got sparks. (It might not be a household you want to live in – but then that’s one of the ways fiction is different from real life.)
In the same way, the hero/protagonist and the villain need to be balanced. If the villain is so super-powerful and clued in and knowledgeable that it seems the hero can't possibly win, then it's not convincing when the hero keeps stumbling into answers and being saved by coincidence. If the villain is so inept that it's hard to see how he can keep functioning at all, then the hero's victory isn't satisfying and savory. Only when the two sides each have strengths and resources and talents is the battle exciting.
What traits do you find necessary to consider when you're developing characters?