There is only one of you.
I have heard over and over the importance of voice and originality. Two things that are of utmost importance to agents and readers. There must be a clear voice and the ms must be original.
Originality--there is after all only one of you. Even if you have a clone or are a twin, your life experience plus your cognitive reasoning = you. In psychology this is the nature vs.- nurture debate that tries to answer what makes you you. Are you a product of your innate abilities that you're creator saw fit to bless you with, or curse you with whatever the case may be (nature). Or are you a product of your environment (nurture)? For the most part, it’s a balance of both. Ultimately that balance makes you unique. Now transfer that on paper and you've found your voice. If only it were that easy.
The voice of your characters--The good and the bad
While I'm writing, I consume myself in the story. I think about plot and characters throughout every free moment I have. I record my notes while driving, take a notebook with me to bed. Every moment I am thinking, breathing and living the story. During this plight, or heightened sense of non-reality, I am learning about my characters: who they are; their tolerance levels; their most intimate thoughts and history.
I love them and hate them.
It's easy to care for your hero. She is the person that is usually given the most attention. She is the one the reader will sympathize with; cry with; cheer for, and eventually makes you sigh when she triumphs. But what about our other cast of characters, especially our antagonist. Don't we have to learn their tolerance, their past, their intimate history? Yes--that may well be the difference between characters that thrive and characters that simply fall flat.
I believe, in order to make your antagonist "real" you need to become intimate with them because, well, let's face it they too are a part of you. Though we are not evil, I hope, we have to become that person who brings that character to life. I think often about Heath Ledger who played the Joker in the new Batman, may he rest in peace. The joker he portrayed was nominated for an Academy Award because he did an awesome job in bringing that character to life. As writers we do much of the same, only we are lucky and have a balance between characters so we are not evil for a long period of time. I hope.
It is not uncommon for the writer to fall in love with their characters. Through different writing circles this is what I hear most often. It's like falling in love all over again. But then I think of Voldemort, Annie Wilkes, Norman Bates---someone had to love them too, didn't they?
The point I am trying to make is that sometimes love is just not enough. As writers we are not only living through the eyes of the good guy, but those of their enemy as well. We live, breathe, walk, and talk our characters and we need to be true to their voice. It can be the difference between a good book and a great one.
So how do you keep your sanity? For me it's family. They keep me sane, enough.