Perhaps the most important factor in successful writing is knowing your audience. Who will be reading this piece, what do they already know about its subject, what do they want to know, and why should they read this piece? If, as the writer, you know the answers to these questions, you will find it much easier to craft a work that meets both your needs and theirs.
Of course, this principle does not apply to some forms of writing. Purely creative works like poetry and fiction can be written entirely for the enjoyment and satisfaction of the creator, with no thought to who might eventually read them. Ars gratia artis.
But if you are writing with a purpose in mind beyond creating a work of art, you will almost certainly have to take your audience into account in some respect, if only in the most basic sense: what language do they read? At what educational level? A primer intended to teach Chinese five-year-olds to read Mandarin that was written in college-level English would be an exercise in futility.
Unless you are a freelance writer, chances are that anything you write will be related to your career or areas of interest. This gives you a head start, but it is important not to assume that your audience knows everything you know, or vice versa.
How do you know what your audience knows and doesn’t know? Much will depend on the nature of the piece and where it will be seen. A plumber writing on her own business website, or in a general audience publication, will make different assumptions about her readers’ understanding of the technical aspects of plumbing than if she is writing for a plumbing industry journal or an online forum for plumbers.
So the first step is to look at other works that have appeared in the venue for which you are writing. If you have been asked to write an article for a magazine or a blog entry for a website, look at previous issues or entries. If you have to write a grant proposal, look for examples of previous proposals that were successful with that funder.
Obviously, the person or organization asking for the piece will provide basic guidance about their requirements and the nature of their audience. But you can go to the next level by asking about their most popular or successful previous entries: what set them apart? What made them work? Was it the engaging style of writing, a depth of technical details, or a strong emotional story? Any of these answers will provide a guide to the kind of writing that works for this particular audience.
A good editor can help with this process as well. Among the most common issues I have with contributors to LF Examiner is authors using a specialized term, expression, or acronym without explanation, assuming that the reader understands the usage. Whether I happen to understand the reference myself or not, as editor, I often speak up for any readers who may not, and point out to the writer that additional explanation may be needed.
Even if you are writing for readers with specialized knowledge, it is rarely a bad idea to write for a level of understanding slightly below that of your readers. Providing a little additional explanation that may not strictly be necessary is usually better than the opposite: writing over their heads. As long as they don’t feel they are being condescended to, readers can easily skip over material they already know.
But when confronted with information too far above their level of understanding, most readers will become frustrated and give up in fairly short order. Obviously, this serves no one’s purpose.
So when you start working on a piece of writing, no matter what kind, spend some time thinking about your readers, and keep them in mind throughout the process. Question your assumptions about how much they know, and try to learn what they want to know, and how best you can provide it. Show your drafts to friends and colleagues (and perhaps even a professional copy editor!) to get fresh perspectives, and be prepared to revise your text to improve its effectiveness.