what are the "rules" when it comes to subplots? Do they have to have an immediate effect on the "main" story or can it just be an ongoing side story of one person figuring in the novel but who doesn't have a major role if it wasn't for the subplot? if it has no influence on the outcome of the other story would it be better to let it become a novel of it's own or would it be ok to include the story of one important event (on the same theme as the novel itself) during the same period for one of the "supporting characters"? it would also add another pov for the main story which i don't dislike.
I am not aware of any rules, and I can imagine you have two plots twined together or separate even. But imho they need to be somehow related, a linking pin, by location, time, character.
Writing isn't a rule-plagued field. A subplot is another, secondary or minor plot that has a seperate plotline from the overarcing conflict. It can either turn into something that ties into the main plot, or it can serve as character development or comic relief: but either way, it should serve a purpose.
Ah nice to hear! the subplot Im thinking of is that of a close friend to the MC who deals with her own issues while the story goes on in the mc's life. It has no direct relation to the story of the mc apart from being a friend, but the theme is about the same as the general for the novel, and I think her crude approach will be a good way of giving some equilibrium to the mc's naiveness, but Im not sure if the story would benefit from it or if the rest of the story would lose credibility.
If the theme is relevant, that's enough reason to warrant keeping it there, but you may want to consider tying your MC in somehow.
As Mallory says, the subplot should serve a purpose. In your example, it sounds like you are using the subplot to develop and reveal character so it serves a purpose. If there is any "rule" you should observe with regard to your subplots, it is that you should remember to tie up the loose ends, resolve the conflicts and bring them to some sort of resolution, just as you do with your main storyline.
thank you James! I'm still thinking about using it or not, it's a difficult decision... I have most of it already written , I just need to as you say finish it and tie up loose ends. In a way I like the idea of a little side-plot in the actual story, but I don't know if I want to distract the eventual reader with it, and in the same time I think it could be interesting... it also has a different tone to it, which might disturb the seriousness of the main plot. Im actually thinking of making this its own novel or at least a short story eventually.
In worst case, why not include it as a short story after the main story? Or split the main story in two and have the side story as a middle? Just a thought.
It's already 6K words and that is in its simplest state plus not entirely completed, I guess I could expand it a lot if I wanted to make it a novel of it's own. It's just that I don't really like when authors do that, start with a story and then make lots of spin-offs from that one, like every character appearing in the first one eventually gets their own novel... That is not the kind of writer I want to be. *shudders*