Once you’ve got an idea for the basic topic of your story, you should also have a pretty good idea who your audience will be. Always keep this audience in mind while writing, whether it’s young adults, 20-40 year old women, fishermen, married people, southerners, parents, whatever. Always do your best to use familiar concepts, language, and tone to that audience. The last thing you want to do is alienate the very people you’ve written your book for.
Don’t write about Snapchat in a book targeted to people over 40, or if you do, write about it in a way that this audience relates to it – as something they don’t quite understand, but their kids all use. Yes, there are people over 40 that use Snapchat, but the idea is to be relatable to the broadest part of your audience.
Similarly, you don’t want to use references to 80’s cartoons in a book targeted to teenagers except in specific, relevant cases.
If you haven’t noticed yet, there aren’t a lot of extremely specific rules in writing, just different methods and formulas for success. I think this is a pretty self-explanatory concept, so let’s move on.