Just about everyone I know had to learn the parts of a formal letter at some point in their schooling. You have the heading, the salutation, the body, etc. I have decided that I am going to revolutionize the closing. I feel like Sincerely Yours or Yours Truly just are not getting the job done. We need to make better use of the closing. Try this for instance:
.....I am pleased that we have been able to bring this matter to a mutually agreeable solution without involving attorneys. Please find our final payment on Invoice #3010 enclosed.
Liking cookies a lot,
Or maybe a little honesty:
Gassy from too many burritos,
Or perhaps something confessional:
Regifting everything you give me,
I think that this will really help a lot of letter writing be more effective. You know, really help the writer connect with their reader.
Just thinking out loud....