1. Internal conflict: with the self, i.e. a character's values, attitudes, prejudices. Think of Salinger's The Catcher in the Rye, or the ending to Ian McEwan's Atonement.
2. External conflict: driven by external forces, such as the environment (natural disasters, anyone?), social classes, the supernatural/otherworldly, morals, culture, duties, obligations, even time.
3. Interpersonal conflict: against other people, like families, friends, neighbours.
For any story to be successful, it has to utilise all three at the same time. A great example is F. Scott Fitzgerald's The Great Gatsby: the narrator, Nick Carraway, feels drawn to Gatsby's hedonistic lifestyle but at the same is repulsed by it (Internal conflict); Carraway and Gatsby come from different social standings (External conflict); Carraway's friend, Daisy Buchanan, feels trapped by her husband's controlling personality (Interpersonal conflict).
It's often helpful to go through these kinds of conflict when editing: does your story lack one (or more) of them? What could you do to emphasise the conflict? Could you intensify the differences in characters, add a time limit to raise the stakes or force your protagonist into making a critical choice?
Remember, conflict is the lifeblood of drama. Happy families make bad stories!
To summarise:
1. There are three types of conflict: internal, external and interpersonal.
2. We need to use all three to get the best story.
3. Rework your characters and your plot to use all the elements of conflict.
Good luck!
Gahks
