4. Make your antagonist at least as smart, strong and capable as the protagonist.
There’s no tension in a story where the protagonist is a Mensa member and Delta Force commando and his foe is a wimpy dolt. Do you enjoy watching a football game when the score is 72–0, or a horse race when one thoroughbred wins by 20 lengths? No, such uneven matchups are boring. The same is true in novels. So, to heighten tension throughout the story, your antagonist needs to be your hero’s equal, or superior to your hero, at least in some arenas. Consider giving the antagonist complementary traits (he’s calm and detail-oriented if your heroine is impulsive; she’s a great team-builder or motivator if the hero is a loner).
In graphic novels, archenemies frequently embody the exact opposite qualities of the superheroes, and are more than a match for them. Whereas Superman’s strength is, well, strength, Lex Luthor’s advantage is intellect.