Close the letter affirmatively. Reiterate your recommendation of the candidate and, if appropriate, invite the recipient to contact you. For example, say, "For all of these reasons, I think Michael will make a fine addition to your team. Should you have any questions, I invite you to contact me at the number or address, above
Then, explain how you know the person and why you’re qualified to recommend them. Include specific examples of the person’s qualifications and successes in the body of your letter, then end with a sentence affirming that you recommend the person for the job or position.