[Your phone number]
[Your email address]
[The opening line is where you state the purpose of the letter and introduce yourself and the business you recommend]
[The body of your letter follows in the main paragraph. You enter all the details of any favorable interactions or communications you have had with the business, what was the outcome of the interactions and why you are able to recommend the company. You may mention the names of some of the people that you have worked with but be sure that you have permission to do so.
Include some specific instances as proof to add credibility to your recommendations as to what qualifies you to be able to recommend the company]
[Invite the recipient of the letter to contact you for more information, and repeat the reason why you are recommending the company]