1. Using An Illegal Cover Photo. The first thing is to use a picture that's pertinent to who you are right now. Don't use a baby picture, a picture of Darth Vader or a famous celebrity. Visitors may think you're trying to cover something up. Also, Facebook has a number of guidelines as for your cover photo as well, like:
- no price or purchase information in the photo (like "50% off")
- a call to action to like, comment or share with your friends
- contact info like web, email or mailing address (there are better places to put this rather than in the cover photo).
- Contests asking for submissions or votes via comments or liking are prohibited.
- All contests or giveaways must be administered within Apps On Facebook.com
- You can't notify contest winners through Facebook on wall posts, messages, chat or the like.
3. Overposting. Yes, it's true, you can post too much. Facebook suggests that one or two posts a day get the most response, and there's some evidence that posting any more (sometimes even twice a day) begins to become counterproductive.
4. Too Much Text. Once again, it's possible to be too chatty, and that can produce negative results. Facebook suggests that somewhere between 100 and 250 characters (which equals a line or two of text) gets 60% more likes, comments and shares. Researcher Buddy Media has found that posts of 80 characters or less have 27% higher engagement rates.
You can read the rest of the mistakes in the Mashable article, but start by following these easy ones, since they can make a big difference in the outcome of your Facebook promotion.