Everyday, I read business email done so informally, it makes me cringe. How do people expect me to take them seriously when they can't even be bothered to write their own emails in a proper way?
1. Proper capitalization
Writing out entire sentences in small letters may be acceptable in instant messaging applications, but they're downright irritating on emails. At the least, capitalizing the proper letters lets me know you have basic writing capabilities. At best, I would not have to sit through acronyms written in small letters, making me look it up in the dictionary, thinking it's an actual word. If you're not sure which letters need to be capitalized, put it through a simple writing software and have it correct your mistakes.
Don't even get me started on ALL CAPS...
Punctuations let me know when you're pausing, slowing down or changing tone. Without it, your copy reads like a never-ending alphabet soup, except it's got full words floating around. Help me out and give me a little rhythm while I'm reading your messages.
3. Incomplete messages
Just because you can understand what you've written doesn't mean I'll pick up on it too. Put yourself in my shoes - if you have the same information that I do, will you get the point? Will you understand the message without any previous knowledge?
Good Writing Matters
Emails may be easier and less rigid than business reports and academic papers. That doesn't make them any less important to write. Give them the attention they deserve.