Guidelines for Names and Titles: The salutation should typically use the person's last name, along with a "Mr." or "Ms." In general, avoid using "Mrs." or "Miss" unless you are certain of how the woman wants to be addressed. When in doubt, default to using "Ms."
If you’ve done that well, they’re going to be asking themselves “How can I make this happen?”, which you answer in the last section of your letter by proposing an action they can take. “Call me at 鴔) 555 to arrange an interview” or “Let’s meet next Thursday to discuss this proposal” or “Order your copy today”. Don’t leave the action for your recipient to figure out. I think a lot of time we lack the confidence to ask for the action we want, and we give ourselves an “out” by leaving it unsaid, hoping they’ll figure it out themselves.