If you are writing to a person whose name you know, always use Dear + their name. If you are writing to a company and you don't know who's going to read your e-mail, write Dear Sir or Madam. Be careful, though! it's always good to check the company's website and find out the right person to write to. Some companies tend not to read the e-mails/letters if the sender wasn't willing to find time to find the information.

First paragraph should always state why you're writing the e-mail. Make short introduction of a company and then write the reason for sending the e-mail. Don't forget to write the name of the company and the fact you're writing on behalf of them!

In the second paragraph you should briefly (!) introduce the company. It's a good idea to organize the information into bullet points. Try to choose information which is relevant for the potential partner's decision. If you refer to the company's website, put the link straight into the e-mail so that they can check it with one click.

If you have some references about the company, send them as the attachment of this e-mail. Don't promise to send them later as it could be too late for such an action.

In the last paragraph state what action you expect from the person you're writing to.

Don't forget about final statements and your name (plus status), which are obvious part of any formal e-mail.

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.