Always put your address at the top-right hand corner of a letter. Do not write your name there (only company's name)!

There is the date below your address.

There is the recipient's address with their name on the left above 'Dear...' Include the name of a person you are writing too.

The 'rules' about the greeting are the same as in an e-mail. Check page 7.

Paragraphing is the same as in an e-mail, which is 1) the reason for writing; 2) a brief introduction of the company; 3) expected action; 4) final statement. Check page 7.

This is definitely one disadvantage of a letter. You can put a website link there, but it requires the person to do it when they are at the computer, which might be later and so they might all forget about it. Also note that in the letter you don't use an attachment and attach, but an enclosure and enclose.

In many guidelines how to write a letter you can find that if you start with 'Dear Sir or Madam', you should end with 'Yours faithfully', and if you start with 'Dear + name', you should end with 'Yours sincerely'. Nowadays, though, it's common to use the phrase 'Best regards' no matter what phrase the letter starts with.