Somebody want something from someone.
There it is. Every story ever told distilled to its essence. Your job is to make that somebody (man, woman, child, alien, beast, fairy, goblin, ghost, vampire, werewolf, zombie, monster, microbe, weather phenomena, or God) feel motivated to the reader so that the "somebody" is going to try to get something (a woman, man, playmate, domination, a beauty, a ring, revenge, blood, who the hell knows what a werewolf wants, [duh! brains], a girl in a flimsy nightie, other microbes, expulsion of humans, or that feel good vibe from knowing you can do anything you want. You must make the motivation seem real.
Why am I blathering on about this? No real reason other than to get you thinking about your characters and what they want. Never forget the motivation. The more main characters you have with specific motivation, the better your story will be. Go watch Casablanca. Go read The Maltese Falcon. Go watch Dogma. What makes these stories tick, aside from other properties, is that all the main characters, and even some of the minor ones, are fully motivated to their goals, even if, as in the case of Rick, the goal changes by the end.
Go forth and write. Make every word and action count. Make Virginia sit up and take notice.