There are different styles which vary in British English and/or in American English.
In either case, if you use ‘Sir’ or ‘Madam’, close with ‘Yours faithfully’.
If you use a name, such Mrs Jones, or Mr Smith, close with ‘Yours sincerely’
The date may be written 12 June 2014 (this has recently become the most used version) or 12th June 2014, not the 12th of June 2014 and preferably not 14 06 06 because as different countries have different ways of doing this it leads to confusion over which is the day and which the month.
Formal letter:
Informal Letter: