Recently, I was reading a new post on the Wordplay blog (link at the bottom of this post) about walking the descriptive line in order to keep a balance with clarity and the story itself. This led me to think about some fantasy and scifi novels I had read recently. While a good author keeps my interest, a great author helps me to understand without making me feel stupid. I don't read these genres very often, so I sometimes find it hard to immerse myself in a world completely different from my own. I need help from the storyteller to be able to follow the plot and picture the scenes.
Now that I think about it more in-depth, this is an important idea for every author. If you are writing about life in northern California, you have to realize that not all of your potential readers have the same background information you do. When people think about California, most imagine the sun, the ocean, and the Hollywood sign. If this is not what you have in mind, then you need to help your reader see what you want them to see.
At the same time, you have to make the story appeal to people who already know what you are describing. You have to find a balance between teaching newcomers and keeping the interest of the experienced. It can be very difficult, so feel free to enlist a friend or two. Preferably one friend who knows what you are talking about and one who doesn't have a clue. Gauge their reactions and adjust accordingly, and you will soon be able to do it all on your own.