A recommendation letter should be more than one or two paragraphs lengthy; a letter this brief shows that you either don't know the individual well or do not completely support them. However, you want to keep the letter short and to the point, so avoid writing more than one page. Generally, letters should be written on standard letterhead using formal language and with a tone of voice consistent with that of an email. If you are unable to write a proper letter, then an email will do. The recommended length for a letter of recommendation is between 250-500 words. Short letters are considered ineffective as they are difficult to read and lack detail which makes it hard for the recommender to express themselves clearly. Longer letters tend to be viewed as tedious by others who may wonder what other aspects of their life you have found interesting enough to document in writing! When writing your letter of recommendation, it is important to include all the relevant information, but also to be selective about what information you include. For example, if the person has only been working for a new company for three months then there isn't much use in including their work history from earlier jobs. Also, avoid mentioning negative things about the person - this will only cause problems when looking for employment. Finally, be sure to follow any specific instructions given by your reference reader.