You've got to write something important: explain a new initiative, make the case for addressing a competitive threat, or simply compliment someone on a job well done.

But if you're not careful about how you write, you could undermine your effectiveness. In fact, mediocre writing can make you look really, really bad.

Although it's easy to put your fingers on the keyboard and tap out lots of words, it's much more challenging to produce writing that's clear and compelling. So take time to avoid these common writing mistakes.

1. Lack of focus. Start by being clear about what this piece of writing is meant to accomplish. Then make sure the finished product achieves your objective.

2. No structure. I just tried to read an article (about, ironically, communication) that was all over the place. First, it covered organizational communication, then what leaders do, then managers' roles, and then advice for individuals communicating with each other. I was so frustrated that I abandoned ship.

3. Not relevant. Your audience members need to know from the start how what you have to say is relevant to them. If they can't figure it out, they will tune out.

4. Full of jargon. Avoid acronyms, corporate speak, and buzzwords. If you absolutely have to use them, make sure you define and explain every one.

5. Pitched too high. Unless you're writing for people like college professors or lawyers or process engineers who crave obscure complexity, stop trying to sound impressive by using a lot of 10-dollar words. Instead, simplify, simplify, simplify.

6. Pitched too low. Although simple is good, childish is not. Unless you're writing to your BFF, don't use text abbreviations or emoticons.

7. Bad spelling. The trouble with Spell Check is that it's not very discerning. So it won't pick up the fact that you typed "poor" when you meant "pore." Or that you didn't mean "principal" when you wrote "principle." Sorry, but you actually have to read your own work to check it.

8. Poor grammar. Most of us (including me, the English major) haven't taken a grammar course since the sixth grade. So you need to make sure you know the basics and look up anything you don't understand.

9. Too much. Even the best writing gets tiring when it goes on and on and on. Long content doesn't respect readers' time. That makes you look inconsiderate.

10. Too dense. We've become a society of skimmers who don't want to read every word--we prefer scanning a document for what's most important to us. So use devices like numbered lists (like this one), bullets, and subheads.

11. Unclear call to action. You want people to take action and your readers want to know right away what they need to do. So make the call to action very obvious.