It may be one of the best-kept secrets shared by small business owners: The human resources department in their small business may be the smallest department in the company, often consisting of one person. This doesn't mean that the person's job is easy - even if your company employs “only” 100 people, your HR person could, potentially, write several staff memos a week on topics as diverse as safety practices and overtime procedures, to reminders about dress codes and holiday parties.

Select One Topic

Memos should be purposeful and targeted, with only one topic addressed in each one. Even if you find yourself with, say, four or five different topics to alert employees about, write four of five separate memos.

This type of “message discipline” should help you stay on task and focused on the main idea in each memo.

Define Your Audience

Take a pointer from the basic format of a memo: “Date,” “To,” “From” and “Regarding” (or “Subject”). It's unlikely that every memo you write will be addressed to “All Employees.”

Take advantage of a memo's obvious appeal: the ability to narrow the audience by department, shift, status (full time or part time) or a different criteria.

Start with a Strong Opening

Unlike business letters, memos zero in right to the point. Immediately state the purpose of the memo in the first sentence.

Invert That Pyramid

Structure your memo in what journalists refer to as the “inverted pyramid” style. This means that information is presented in descending order of importance, starting with the most important information first, just as in a news story.

After that attention-grabbing first sentence, organize your memo so that supporting information is presented in step with its relevance. This way, if an employee stops before the end, the most important info is the part that's been read.

Keep it Short

One page is an ideal length for most memos. If you've narrowed the message, this should be a relatively simple goal to accomplish. The length may also force you to decide which information is essential and should be included, and which information may be superfluous and should be omitted.

Clarify the Action Step

Leave no doubt about what you expect employees to do after reading your memo. Should they read and initial a new company policy? Do you want them to enroll in a conflict resolution course? Must they visit HR and fill out a form by a certain date?

Make your expectations clear.

Anticipate Reader Questions

It's impossible to “get in the head” of every employee, but you should do your best to anticipate questions and reactions to your memo – both to stem confusion and to ensure that your instructions are followed. Be sure to give employees the ancillary information they need, or at least steer them to other people (like yourself) who can help them fulfill the dictates of the memo.

Consider Text Layout and Design

Blame the web or give credit to smartphones (or the other way around), but many people have become accustomed to seeing large headlines, small headlines and bullet points break up blocks of text.

There's a good reason for this: Research studies show that these conventions improve readability.

Expect a Leak

If you've been burned once, you'll never again overlook how “one little memo” could upend your business. To prevent such a painful “burn mark,” assume that your memo, in today's hyper-connected world, will be leaked – say, to a competitor, to an industry publication or to a generally nosy public via social media.

If you're not prepared to deal with such a disclosure, consider postponing the memo's drop date until you are.

Heed the Experts

There is no shortage of resources to help you write effective memos to your staff.

If you have time for only one, read Robert Behn's “The Craft of Memo Writing.” This lecturer at Harvard University's John F. Kennedy School of Government has taken pains to copyright his work, but his humor shines through nonetheless.