Microblogging for business - keep it about customers

If all you do is tell followers what you're selling, then customers stop paying attention.  You can always improve your tweets & status updates by changing the focus from today's special on the menu to a special moment with customers, like photos from an event (preferably one that's related to your business over your nephew's ballgame).

Burying the coupon code and saying something about a recent winner up front is more interesting.  Get the pitch in, but compelling or interesting factoids make you more of a friend than a "pitch person".