As someone who writes romance at the heart of her work, I often find these threads difficult. But I suppose I will play, too:
-- The character who is your MC, if you are writing something that involves danger, action, etc. should be the one saving the day. This is usually a problem with FMCs. I can't count how many books have ticked me off because what I've ended up reading is a girl telling me about how a hot boy saved the day.
-- It's okay to have a dangerous or questionable love interest, but you're going to have to work to convince me *why* he actually deserves the FMC. If his danger is external and he is good to her, I feel you're a step closer. If he is consistently an ass to her, you're probably going to annoy me.
-- Characters need good and bad traits. You cannot split this down the middle like "Here are the good guys" and "here and the bad guys". Your heroes should have issues that will make them feel Real. And your villain / antagonist should have virtues that make the reader think if you'd chosen you could have told their story.
-- If you're going to do something that's been done to death -- Vampires, Werewolves, Dystopia, fairy tale retellings -- have a reason. Why should I read your book? You really need to convince me because there are a lot of these to choose from. (*points at self here, as this is my own area*) What can you give me that I have *NEVER* read before? (While I don't believe anything is fully or truly new I feel there is value in new presentation.)
-- Your LI needs to be more then just gorgeous. "Gorgeous" doesn't tell me anything about him. It has no qualifiers other then to say he wasn't ugly or average. A gorgeous guy might work on a magazine shoot, but books are about words and so its the soul of the character that I care about.
I think that's enough for now. Hope I helped.
