STYLE
The human eye reacts differently to a computer screen than a piece of paper, so how you format your email is vital. Use short, succinct sentences that get to the point immediately; remember, your goal here is to dispense important information, so give that to the reader right up front. Always include a greeting and a signature, and use as many line and paragraph breaks as possible; this makes the email easier to read. And resist the urge to write a book. Business emails are better off short; the equivalent of a page or so is sufficient.
TONE
For better or worse, the Internet breeds a nasty habit of informality. It's okay to be slightly informal with your email (people tend to expect it lately), but don't write as if you're talking to your mother or best friend. You need to strike a balance between traditional formality and e-mail informality. Think about your recipient and how they'd most likely write an email. What words would they use? Would slang or jargon offend your readers? Use these considerations to create a concise, customized email.
GRAMMAR
Informality, whatever its root, does not excuse grammatical errors, and these can damage your email. Grammatical errors show that you didn't put much time into your business email and you probably don't care much about your message. Go through your email carefully to make sure you have spelled correctly, and you have fixed all grammar and punctuation mistakes. Remove all redundancies and get rid of any clichés. Recipients, especially professional business people, will appreciate your attention to details and they will respond better to your message when no errors exist in your email. Most writers use WhiteSmoke Software (www.WhiteSmokeSoftware.com) or StyleWriter (www.StyleWriter-USA.com) to assist with correcting grammar.
RESPONSE
Since email is an immediate medium, and a highly accessible one at that, it's far easier than in paper letters to request a response -- and far more likely that you'll get one! Before signing off with your signature, be clear about what you want the recipient to do. Need a response via phone or with certain information attached? Say so! Your recipient will have a difficult time responding if they have no idea what you want from them. But remember: be polite when requesting action. There's little worse than an overly forward or pushy ending.
Brian Konradt has been a professional freelance writer for over ten years. He is founder of LousyWriter.com ( http://www.LousyWriter.com ) and LiteracyNews.com ( http://www.LiteracyNews.com ).