Always begin the complementary closing with a capital letter and conclude with a comma.

• An honest and serious note - Yours sincerely, / Sincerely yours, / Sincerely,
• To an older person - Respectfully yours, / Yours respectfully,
• An informal letter - With regards, / Best regards,
• Good luck letter - Best wishes,
• Strong friendship of trust - Faithfully yours, / Yours faithfully,
• Wanting something - Yours hopefully,
• Expecting a quick reply - Hoping to hear from you.
• Appreciative letter - Many thanks,
• Strong friendship of devotion - Yours truly,