If you look at your story objectively, do you think it’s predictable? Do you think that the happenings would be expected? Would the love be requited, would plot take a turn, would your reader be surprised and taken off-guard? Staying away from formula means staying away from predictability. Avatar was a wonderful movie to watch, but we all knew the moment we saw it that he’d be riding that really giant orange/red dragon everyone feared in order to secure the respect of the people. Avoid pointing things out... in many stories, the author will mention something seemingly innocuous ... a broomhandle hitting the floor... a window with broken shards of glass... it's transparent and it takes away the surprise. The reader is automatically going to know that it’s going to be related to the next bit. Don’t be obvious. It’s annoying.
The tired ex-soldier who needs revenge; the comedic sidekick; the jaded warrior, the strong chick that really secretly wants to be objectified, pursued and rescued; the untamed, willful woman who is tamed by the strong-willed hero; the dogged underdog, the grunting strongman... let’s face it; you might as well be picking characters from an MMORPG character builder these days... there are so many old, boring archetypes. Your characters are supposed to be real people in the story. They have backgrounds, they have motivations, even the good people have flaws... they don’t do things just because, they hesitate before they jump into the fire, the bad guys can be likable, heroes can make mistakes.
Pitfall: Recycled Settings.
Impersonal and recycled settings can get old quickly. It’s one thing to create settings, but another to make them yours as an author. What makes fiction good is the believability of the places you describe, the detail that puts the reader in your head. Pulling from your own life, your loves, you can create something intriguing for others to ‘see’. Pulling from the basic novel 101 settings, like Middle Earth, or New York, or L.A. with no personal references to it, no details is going to make it seem generic. It’s the little restaurants nobody knows about, it’s the shape of a window, and it’s the quality of sound in a room... you have to put your readers somewhere they can picture; and not rely on past authors’ renderings to support the ‘realness’ of your settings.
If you just write something that seems generic, or like another author’s work, it’s nothing but Fan Fiction. What makes a story readable isn’t just the story, it’s what is added of the author’s own personality and life experience. Even the most bizarre places should still be believable, which means you have to inject some of yourself into what you write, and not just write a story where A character goes to B character and fights them over C character who is in D location.
Don’t be formula! Don’t be predictable. Your characters should be as real as the people in your life, and don’t create worlds that are someone else’s... inject your own world, whether or not it’s somewhat fabricated or it’s a study of the neighborhood outside your door. As a reader, I implore you. As a writer, I implore myself. ;)