So, what is internal conflict? It's the internal battle(s) going on inside each character and the way the writer reveals the character arc/growth. The internal conflict should play off of the external conflict, but doesn't always need to correlate one-to-one. And plot points can be used to give a character what he thinks he wants, although it does nothing to move the character closer to the external goal. Sometimes, the whole point might be to allow your character to discover that he didn't actually want what he thought he wanted.
The best advice I've found on how to effectively use internal conflict comes from Fiction Factor:
Find the main character's Achilles' heel (the root source of his/her internal conflict) and stomp it (external conflict).
In my opinion, the internal conflict the writer chooses to include is really what makes a reader fall in love with a story (or hate it). The internal conflict is the part the reader can personally relate to and so, if we writer's don't make it believable enough, or interesting enough (pages of "should I wear the red dress or the blue skirt today?" narrative isn't going to do it) then the reader won't feel emotionally invested in our stories no matter how amazing the external conflict is. And, we have to be careful to resolve all internal conflict by the end of the story or else the reader will feel let-down.
What do you think? Do you put a large focus on the internal conflict for the characters in your stories? Do you think about the internal conflict and character arc for characters other than the MC/POV characters to make sure their actions/speech reveal their inner turmoil as well?
