I have just started working on a novel. The idea(s) is/are original to me as far as I know. But what if I inadvertently use someone's idea? I guess it is OK to generally use a plot, they are pretty much recycled anyway. But what if I accidentally use someone's theme or main ideas? I suppose I won't get published if the other writer beats me to the punch or is well known. But is there some sort of due diligence I should engage in before I begin?
I do know how the google works. But my question is more general. How much time/effort should I devote to this sort of thing?
Every story has some elements that are similar. For each thing in common that your story has with someone else's, there will be 1,000 differences...
Stop worrying. You are obviously not stealing someones story. Even if there is another story out there with the same plot idea (written by someone else) your story (written by you) will most certainly turn out completely different. I think this is a common fear for new writers. Keep writing and good luck.
I wouldn't unless it is glaringly obvious. My MC in my first book changes into a falcon. Didn't realise until I watched it with my kids my favourite 80s cartoon character does as well lol It will happen I see lots of elements of cartoons and books I have seen a read in my stories or sayings I have taken from friends.
Just go with it. Keep writing. Even if when you start out, you've stolen someone's plot, by the time you finish, it'll be your own. There's a lot of literary theory out there that claims there's a limited number of plots, so it's your details, your unique voice and perspecitive, that will really make your writing in the end.