Ending a letter really depends on who the letter is to and the purpose and contents of the letter. Official letters where you know the name of the recipient could be ended with 'Yours sincerely', whereas for more formal letters where the recipient is an anonymous Sir/Madam, 'Yours faithfully' is more appropriate. Less official letters could be ended with 'Regards' or even 'Kind regards' and for casual letters, 'Take care', 'Love', 'See you soon' could all work too. Use your own judgment and also have a scan of letters you have received to get ideas.
