DISCLAIMER – “The creation of a truly villainous character can become especially intense. Try writing about them in smaller chunks than you ordinarily would. If you don't take a small break every half-hour or so, you may find yourself absorbing a portion of the villain's negativity, which can affect your relationships with the people you care about” [http://www.wikihow.com/Create-a-Credible-Villain-in-Fiction]
Disclaimer 2- everyone writes as if the villain is a “he” feel free to substitute “she”, some of the best villains are female ie: the White Witch in Narnia, Bellatrix Lestrange
DEGREES OF VILLAINY – The genre you are writing in will dictate the type of villain you create. The degrees of villainy range from the nosy next door neighbor to the psychopathic killer to the mastermind wanting to take over the world and many levels in between. Pick a style that is a good balance to your hero. “Your villain has to have enough power, of whatever nature, at his disposal to make him a credible threat to your hero… David wouldn’t have gotten nearly the press he did if Goliath had been 5’9” and asthmatic.” [http://www.magicalwords.net/really-i-mean-it/how-to-build-a-villain-by-jim-butcher]
BACKSTORY – every villain needs one, even if the reader does not see their whole story. You as the writer need to know where the villain came from.
“Think about what happened to make that character the way she is. You may never share your villain’s life story with your reader, but to make a complex, interesting villain, you need to know.” [http://www.writersdigest.com/writing-articles/by-writing-goal/improve-my-writing/3-techniques-for-crafting-your-villain]
Consider these points while keeping in mind that villains are broken:
-What motivates him?
- Why does this particular desire drive this character?
- Is there anything that would satisfy this desire?
How far would you go to achieve this goal?
What if you didn't care who you hurt?
How would you rationalize your actions?
-What traits and talents must he have to perform his role in the story?
-What additional traits, talents, or back story should I give him to create the sense that he is a real person and not just a cog in the plot machinery?
-What would make him interesting? [http://suite101.com/article/creating-memorable-villains-a43842]