Interior Dialogue:  Readers don’t trust dialogue.  Have your characters think, and have what they think be juxtaposed to the dialogue, showing a new angle.
 
This one I learned the hard way.
 
When I first started writing novels, I was under the impression that the best writing was like a screen play, all dialogue. So, I set out to write just that…as much dialogue as possible with description in between.
 
I would figure out what the character wanted or was thinking and I would write it down as something he said.
 
Back then, I had two friends reading my work—the same two who set me right about senses (Von Long and Danielle Ackley-McPhail). When I finished a chapter, I would send it to them, and, invariably, they would write back, along with a request for more sense impressions, “What is he thinking?”
 
To which, I would stare at the page in absolute puzzlement and then, gesturing at it wildly, cry out, “But I just told you what he was thinking! He said it out loud!”

Then, one day, it struck me. 
 
They did not believe him.
 
No matter what I had the character say. Unless I did something to indicate in the text what his opinion was, they did not know if he was telling the truth or not. They did not know if his happiness was true or feigned. They did not know if he agreed with his words or was just saying them to be polite.
 
No matter what he character said, it never occurred to them that this was also what he was thinking.
 
And that was when I realized that internal thoughts are another form of “The Trick”—another chance for an author to show a contrast between two ideas in the story, in this case, what is being said and what is being thought. And in writing, as in drawing, it is contrast that brings out three-dimensionality.
 
Now, adding contrast does not mean that what a character is thinking always has to be at odds with what he is saying. Some characters say what they mean. But showing thinking gives the author a chance to fill in the story, to add shading.
 
Is the character worried about what he is saying? Is she excited for a reason she has not yet put into words? Does she have a hidden agenda, good or bad, that she does not wish to reveal. (Hidden agendas can be good—picture a character trying to subtly discover a friend’s schedule so as to plan a surprise birthday party, for instance.)
 
Interior or internal thoughts and feelings can be indicated in two ways. The first is to put the thoughts on stage:
 
1)         She loved the old couch. It pained her to see it in such bad shape.
 
 
Or, even:
 
2)         She thought, “I love that old couch. How sad that they let it get like this.”
 
The second is to show without telling:
 
3)         She ran her hand slowly over the old couch, stroking its worn upholstery and running her finger along the crack in the polished wood of the arm. 
 
Or, show with some tell.
 
4)         She ran her hand slowly over the old, worn couch, sad to see it in such a state of disrepair.
 
Which method is better? Whichever one tells the story. Many successful works use a mix. The second one is probably the least common. Direct thoughts in conversation are used occasionally, but most works do not rely on them, unless they have some special gimmick that makes it work.
 
Modern writing books push the third: showing with no telling. Showing is great for two reasons. One, you often have a good chance to use either visceral reactions or sense impressions, both things that can make the story more vivid for the reader. Two, that is how we tell what other people are feeling in life, but seeing their expression, how they move, and what they do.
 
Sometimes showing only works. I think its pretty clear in my example above what is going on, but, as a reader, I find that sometimes they do not work. Not every reader has the same expectation of what a certain gesture or action means.
 
If the expectations do not match those of the author, the reader is left going, “Huh?” This happens to me with certain writers I have read. (They have all been women, though whether that is causal or by chance, I do not know. Still, I think of it as ‘that mistake women writer’s make. ) I get to a scene, something happens, the character has an emotional reaction, and I am left going…”Bah?” with no idea of what caused the character to have that reaction.
 
The internal thought responsible for the motivation of the character just did not communicate it self to me in the scene.
 
I also notice that some of my guy friends seem even more puzzled by these same passages than I am, as if they are missing even more subtext. I often discover that these same fellows have entirely missed the emotional subtext supposedly conveyed in a ‘show not tell’ scene.
 
So, personally, I prefer a mix of One and Three, or Four, unless the particulars of Three make the meaning plainly obvious. If I were writing the scene in the examples, which option I picked would depend on the purpose of the scene. If it was important to either the plot or character development, I would go with:

         She ran her hand slowly over the old couch, stroking its worn upholstery and running her finger along the crack in the polished wood of the arm. She loved the old couch. It pained her to see it in such bad shape.
 
If the matter were of very little importance, I would use something more like Example Four.
 
I would not use Example Two on something as unimportant as a couch unless I were writing THE HAUNTED SOFA, A GOTHIC FOR OUR TIME, and her direct thoughts were being overhead by the mind-reading entity dwelling in the old couch.
 
Am I good at internal dialogue? Sadly, no. I believe it is my weakest area, but, at least now—thanks to my friends questions–I have the gist if it, which is: use internal dialogue to add contrast to the story, help fill in background, and hint to the reader the causes of the characters emotional reactions.
 
When done right, Internal Dialogue gives the reader a deeper sense of three-dimensionality and depth, hopefully, without weighing the story down.
 
I learned the hard way. Maybe, just maybe, you won’t have to.