Every Hero needs a Dr. Watson
I had the revelation that I needed a Dr. Watson when I was writing my first novel. Which will never see the light of day but from which I nevertheless learned a lot. I realized that my heroine/detective was puzzling out the mystery almost entirely in her head. Lots of thinking, not so much action. I suppose I could have had her discuss her conundrums with her cat, but as you know, cats don’t do supportive or empathetic. And certainly not second fiddle.
Then the revelation. That’s why Sir Arthur Conan Doyle, author of the Sherlock Holmes novels, wrote in the character of Dr. Watson, faithfully following Holmes everywhere. Yes, the conceit is that Watson is recording the stories for posterity, but in fact, it is a way to allow the protagonist to work through the issues of the novel in a more dynamic way.
Not to say that talking to someone is an adequate substitute for action which moves the plot forward, but it does have the advantage of being slightly more active than inner dialogue. It also introduces the possibility of conflict or debate if/when Watson disagrees with Holmes’ analysis. Which rarely happens with the omniscient Holmes, but you get what I mean.
(Almost) every novel needs a Dr. Watson
I think most novels need a Dr. Watson. Can be a best friend, a colleague at work, even a stranger on the subway.
Look at your draft to see if you have a Watson-like character that not only can get the protagonist’s thoughts out of his head and into speech but also potentially challenge the logic, wisdom or even morality of the hero’s intentions. Or elaborate and refine his plans.
This Watson character can, in and of himself, add a dimension to the story by having a definite view which conflicts, or at least must be reconciled, with the hero’s. Action-oriented versus cautious; retiring or larger than life; pragmatic/principled; empathetic/hard-nosed. You get the picture.
You don’t need to go crazy either in the number of contrasts or extent of the difference. Otherwise, you risk falling into caricature or stereotype. But a strong secondary character can not only enhance the story but your reader’s interest in it.
When you don’t need one
Naturally, if your hero is primarily caught up in personal angst, a secondary character providing a listening ear and even objections, might not be appropriate. When the protagonist’s raison d’être is introspection and tangling himself in the weeds of his thoughts, then allowing the story to flow as intended may be the right answer.
But if you have a worry in the back of your mind that your hero is doing too much thinking and not enough action, Dr. Watson may be your ticket. The discussions don’t in and of themselves constitute action but they seem to promote it. Give it a try.