Successful memos generally share the features listed below:
1. Subject headings. Memos contain such guideword headings as To, From, Date, and Subject. These headings help readers immediately know the date, the sender, and the purpose of the message.
2. Single topic. A successful memo discusses only one topic. Limiting the topic helps the reader concentrate on the subject and take action on the subject quickly. A single topic also makes it easy to file and retrieve the memo.
3. Conversational tone. The tone of memos tends to be conversational because both the writer and the reader are familiar with each other. Therefore, you may use ordinary words, first-person pronouns, and occasional contractions, like don’t, I’m, you’re, or we’ll. Yet, this does not mean you should be casual with your writing. You shouldn’t include any remark that you wouldn’t make to the face of your colleagues.
4. Conciseness. As an efficient form of internal communication, memos contain only what you intend to convey. Often you do not have to provide background information when you are certain the reader knows about the subject discussed in the memo, nor do you need to make as much goodwill effort as you do in letters to your business partners outside of the organization.
You should avoid wordy expressions and sentences. For example, don’t use "because of the fact that," or "I am writing this memo to inform you that…"
5. Visual signalling. Effective memo writers highlight important words, phrases, points, and sections with
• numbers or bullets listed vertically;
• boldface or italics;
• headings and subheadings.