Want a full-bodied story? One of the keys to getting there is not skimping on your antagonist. In fact, your antagonist could very likely be the most complicated character in your story. After all, his/her actions are usually driven by a need much deeper than that of the protagonist. The protagonist's actions are simply responses to the moves of the antagonist. It's the antagonist that sets everything in motion.
You should strive to make the antagonist a real, three-dimensional character - driven by the pain or anguish of past memories. Make the reader empathize with him. Make your reader think 'I can see where he's coming from.' What was it that turned the man into the monster? Was he a victim of some greater fate?
I'd like to use 'Willie', the antagonist out of my novel 'I Am Maker' as an example. In his mind - he's completely justified in what he does. Willie feels cheated by the fact that in his case, blood wasn't thicker than water. He feels left behind by his own kin. And when it comes right down to it, the real monster isn't him - it's the protagonist. Now in this story I don't think that a reader would actually ever empathize with Willie, simply because Willie is just so damn mean. But at least they see that he has feelings, that he's willing to stand up to a superior force, and that his actions are driven by the events of the past.
In another story that I'm trying to get published 'Last Days of the Dinosaur' (you can read the first chapter on my web site www.jonathonwise.com ) I've taken it a step further. At the beginning of the story, most readers will think that the antagonist is a standup guy. He tries to help those in need and puts the welfare of others before his own - even to the point of risking his life. It's only when the outcome of that heroism costs him more than he can bear, that his actions turn antagonistic. Even as the story progresses we understand the pain and suffering he continuous to endure. He feels helpless to stop the downward spiral of his actions. That is until he realizes that there's one man who CAN end his pain. It's the hope of finding that one man that drives him into becoming the full-bodied antagonist he was destined to be.
So remember to spend as much effort in building the character of your antagonist as you do the protagonist. Just as you feel more for a hero when you know that hero is actually putting his life in danger to save others, so too will your villain benefit by showing his vulnerabilities and suffering.
Until next time, keep your writing real. J/W