One tweet is usually sufficient to inform people of an announcement. Maybe mix it up with another differently worded announcement 8-12 hours later, or something. The majority of your tweets should either be talking WITH other people (as opposed to at them), or passing along information your tweeps will find useful.
Most people simply unfollow or ignore folks whose tweet content is mostly "hey, look at me!" stuff. Twitter is about connecting with people, not selling things.
Most people simply unfollow or ignore folks whose tweet content is mostly "hey, look at me!" stuff. Twitter is about connecting with people, not selling things.