I'm particularly interested in this in the context of a new novelist. Are subplots necessary for a successful, good story? Do most novels have them? I'm not sure I fully understand how to write a subplot and the main plot and have them all be pertinent to the ending. I don't want to write a subplot just for the sake of saying I have one.
Do you have two characters who talk to each other about something other than the main plot of your story? If so, you have something to build a subplot on. If you don't, is your plot so all encompassing that two people in that situation would never talk about anything else? Have your characters all known each other for a long time? Wouldn't they then already have a relationship built up outside of the main plot and those relationships can be part of a subplot. If your characters have all just met, they are coming together in a tense situation and will want to know something about each other (such as, "will I be able to trust him at my back when we are in a tight situation?"). Don't think of subplots as just ways to make the book longer. You are developing character and adding texture to what is happening, perhaps, if you want, even giving you something that will lead to a sequel.
This is all just my opinion, but the one novel I wrote and finished sucked, in part because I had no subplots.
A tree doesn't just have a trunk. It has branches too.
I'll use life as an example too because it works well. In life, your 'main plot' is say, doing well in that job interview you have coming up. Your 'subplot' or 'side plot' are all the things you have next or beside that which you are also doing. It is inevitable, that if you are going to create something with depth and a sense of realism that it will have more than just one main plot.
Aside from that, subplots are great for the following things:
Developing a character(s)
Boosting the main plot, helping it develop in some cases
Creating more depth by adding more layers to the story
@SaraCosta also made a brilliant point about two common types of subplots. One that gives a notion of social networking in the world, and one which can impact the main plot. For example:
There's a job interview coming up. <- main plot
My friend organised to hang out, etc etc. <- sub plot
Because of that I missed the interview. <- effect on main plot
The main plot can still be developing meanwhile this subplot can end having an effect on the main plot.
In conclusion I believe that to write a successful story, subplots are definitely necessary.
The book Invisible Ink by Brian McDonald helped me with this.
The very first sentence is, I don't like the term subplot; I think it confuses people. He prefers referring to them as "supporting plots" (rather than "Subordinate Plots") as they should exist only to support the main plot of your story. Not to add "depth" to the world or anything as benign as that (you should be doing that anyway).
If you have a story where the Main Character (MC) has fallen for a woman and will do anything to win her over; a point of conflict might be that the woman has another man who wants her. A pertinent subplot might be:
Have the other guy be an outwardly charming bad guy; the MC wants to unmask him, in the process we learn more about his character and how good he is in comparison to the villainous swine.
Have the other guy be a good guy; the MC realises his faults compared to him, and betters himself, which the girl notices. We now have more character development and root for the MC to woo the girl more; we've seen him overcome harsh realities of his personality.
In light of that... you don't need supporting plots coming out your ears just to elevate your main plot. Unless you've got a sprawling multi-book series then you can't afford to have dozens of offshooting mini-stories that you can't wrap up before or during the end of the book.
Try to be concise; summarise what your character wants (or what the plot is), is there any other kind of story you can bring in to play that will elevate that main point while not appearing out of the blue for the reader?
While Terri Simon makes a great point, I'd like to add my two cents.
I find that sometimes the protagonists can become all too important in a story (especially in a romance). Their dramas will be always upfront and their lives will become a claustrophobic bubble (at least for me). If there are secondary characters going through difficulties, one can use that as a subplot to bring diversity of people and problems and to burst that bubble.
For example, the hero is going through a breakup and is focused on that personal tragedy. Then a friend phones him and asks for his help finding a job because the company he was working for went bankrupt and he can't even afford next month's rent.
Two important pieces of advice:
don't create a subplot for one scene and forget about it. So the friend is looking for a job. Maybe next chapter he can text the protagonist saying he got a job and, four chapters later, maybe they're talking at a bar and the friend comments how losing his job was the best thing that happened: he's so much better now. The mentions only take a few moments, but it will help to create an illusion of a world outside the protagonists' immediate needs, feelings and actions.
I believe there are two types of subplot:
2.1 the type that gives a notion of a wider world and social networking but doesn't really impact how the main plot evolves but helps fleshing out characters and world;
2.2 and the type that does affect how the main plot evolves (maybe the protagonist meets their soulmate while helping his friend)
When writing a story, you always have an overarching goal for the protagonist. The question you need to ask yourself is:
How did they reach that goal?
The terms Cause and Effect can play heavily in developing a gripping story that doesn't just move from point A to point B.
If your story is about a protagonist wanting to defeat an antagonist, it would be stale and a waste of effort to elaborate the background of a character, flesh out the world, and then just have the 'hero' instantly defeat the antagonist. Think about what else goes on in this world, make the story take place in a diverse and realistic environment.
- Is it a world plagued with dragons that the populace fears?
- Are there social groups that dislike another group?
- Do the companions of the protagonist have any dark background or relations with a syndicate?
- Is there some reason that a certain rare commodity has suddenly become plentiful?
Once you think of some events that may take place in your world, link it with your protagonist's overarching goal.
- Could the dragons that the characters meet be driven out their home by the antagonist causing them to distrust humans? Could these dragons know a secret way into the antagonist's impenetrable lair?
- Does the protagonist learn about the past of the discriminated social group, and learn of the antagonist's connection with it? Can he use this as a way to peacefully neutralize the antagonist at the climax of the story?
- Are the companions hiding something that will be relevant in other parts of the story? Why are they not revealing it? When they do reveal it, does it harm or help the protagonist at his most crucial moment?
- Could the commodity be inflated by the antagonist to perform some evil deed in the world? Could it be originally played off as some interesting product - or improvement of society but actually later be revealed to help the antagonist's ideals?
Just remember that no matter if your world is a steampunk dystopia, the depths of outer space, or even a modern rendition of your hometown, there are things that are happening that aren't just related to defeating the antagonist that you require to flesh your world out more.