The villain has to be one of the main ingredients of a story. Just as cookies or bread won't rise without flour, neither will your story if there isn't a resistance to your hero's journey. It's also like biking. Yes, you can bike a few miles, but it won't really be an interesting story if you don't encounter glass, roadkill, branches, or (worst of all) hills.
Villains come in all shapes, sizes, approaches, and even species. Scar from the Lion King isn't any less a villain than Mr. Wickham or Lady Catherine DeBourgh from Pride and prejudice, and vice-versa. The question is: What type of villain do you want? They need to be a solid fit to your story, and a hard obstacle for your hero to face.
Let's examine the parts of a villain's role:
1. Basic personality.
A. Strength.
B. Flaw.
C. Skill or hobby that may be useful later on.
2. Motivation.
Why do they want to get the girl, steal the painting, or destroy the world (or all three at once)?
3. Lifestyle.
Basically, look at the hero's template, and fill it in with the villain's answers. But you can do all this, and the villain will still turn out flat. One way to solve this is their approach. The modern Sherlock's Moriarty is a cold-hearted murder, but he isn't all bluster and anger, in fact he can be very awkward (besides the fact that he sounds like an old British woman).
Here are some tips on making a villain stylish:
Make them sympathetic:
"That’s how villains get you, she (heroine) knew. You feel badly for them, and next thing you know, you’re tied to train tracks." - Catherine Valente, The girl who fell beneath fairyland and led the revels there.
Make them see them have their own philosophy:
"Fair is foul and foul is fair." -William Shakespeare, Macbeth.
"Shakespeare's villains are fabulous because none of them know that they are villains. Well, some of them do." -Ian McKellen.
Make them capable of being a hero:
"History is moving pretty quickly these days and the heroes and villains keep changing parts." - Ian Flemming.
Either make them entertaining and loveable, or someone you really want to kick in the mouth:
Which would you rather hang out with, Loki or Ronan?
Establish their personalities:
If they're quiet and only resort to violence as a last resort, when they start yelling and swinging battle-axes around you'll know that they (A) mean business, (B) have broken out of character, or (C) have lost their minds.
As a side-note, not all villains have to be alive. Take the storm in The Day after Tomorrow. It isn't a living creature, or the weapon of a living creature, it's just a storm. But it poses extreme threats to the hero's quest of going to New York City to save his son and his son's quest to survive and keep the people around him safe. The storm even makes some problems that aren't exactly part of it's weather pattern, such as releasing a pack of hungry wolves from the zoo.
So have fun!
(P.S. If you run out of ideas, just find a fluffy white cat and start stroking it.)
