Audiences come in various sizes, so the idea that you will be able to appeal and relate with every one of your patrons is a pipe dream. When you are writing a piece of literature, you need to decide two things before you begin: Who are you writing this piece for, and is your target a part of your particular niche?
When I say to define "who" your target audience is, what I mean is that you need to decide whether you are writing for somebody you're expecting to understand jargon and colloquialisms, or whether you will need to explain everything with smaller words for them.
For example, if you are writing a childrens' book, you will need to discern what age group you are writing for, and use sparingly any intricacies or particularly difficult words. Perhaps go online and search for some vocabulary lists to find synonyms for, that way when a child reaches that point in your book they can ask what it means and an adult can tell them "auburn just means reddish-brown."
Congratulations! You just contributed to that child's vocabulary!
I remember when I was a child playing video games was one of my most profound and impressional forms of media. Very often I would ask my grandparents the meaning of different words I came across. One example, from a collectible trading card game, was the word "ante," to bet.
Suppose, however, that your target audience is not children, but teenagers? Do you want to sound hip? Cool? Then you need to partake in their other forms of entertainment. Figure out what they enjoy watching and reading, and in turn watch and read them yourself. Familiarize yourself with their language and jargon.
When you are writing for a large, varied audience, be sure and write in the meanings to all of your jargon. Remember, if you weren't trying to explain to your audience thoroughly the subject you're writing about, you wouldn't be writing about it. So as not to insult, however, you can rely on subtlety.