The best way to write a letter of recommendation is to start out with a formal greeting, or using "To whom it may concern" if you don’t know the recipient. Follow the greeting with 2-3 sentences of praise for the person you’re recommending.
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