Keep in mind that most errors are unintentional, and realize that most businesses and organizations want to address and clear up complaints quickly in order to have satisfied customers or members.
Be brief. Keep your letter to one page, and write short paragraphs, rather than long ones.
Be honest and straightforward, and include sufficient detail to back up your claim and to show that you have thoroughly researched the subject. However, omit irrelevant details. Keep your letter concise and professional.
Maintain a firm but respectful tone, and avoid aggressive, accusing language.
Send only photocopies of receipts and other documents, and retain all originals. Keep a copy of the letter for your records.
In many cases, you can increase the effectiveness of your letter by getting several others to sign it with you. This is particularly the case when trying to influence or change legislation, denouncing material from the media, and so forth.
If a company has repeatedly given you bad service and refuses to correct the situation and you feel that your only recourse is to pursue legal action, voice your feelings in a tactful but firm way. However, don't threaten legal action unless you are willing to follow through with it.
If your letter focuses on a single individual, avoid making generalizations about the company or organization.
If you need to make a complaint to or about people that you will still have contact with on a regular basis, your letter needs to accomplish its purpose without destroying the relationship. Use tact, and be direct, but respectful.
Include your contact information (name, address, phone number, and e-mail address), if desired, so that the person(s) can reach you to discuss any questions or concerns.
If a first letter does not bring action, assume a stronger but still respectful tone in the next one. If two or three letters do not resolve the problem, send one to the president or CEO of the company or entity. In each case, be firm but polite.