Stop mass broadcasting them.
I would take this one stage further and focus on the culture the media creates through its endless cycle of fear-mongering before a shooting even occurs. This leads to other people being viewed as a potential threat and an active and conscious concern about personal safety. I would say that is the most noticeable difference when traveling through the US when compared to other countries in regards to gun violence.
and the amount of people that die from overdoses each day is about the same as if a 747 crashed full of passengers each day: http://www.drugabuse.gov/related-topics/trends-statistics/overdose-death-rates Should we stop prescription drug sales too? Im not trying to change the subject, I'm making the point that people die from legal things all the time. Car crashes kill people -- should we outlaw cars? I have reasons to say that we should not mass broadcast mass shootings, especially when it is a single man or woman who acts alone and for motives that can only logically be described as a self promotion/remembrance. 9/11 was a well orchestrated and funded terrorist attack that required many participants and, as you stated, lead to the deaths of many many people, changed the landscape of an entire city and ultimately a nation. Shootings and 9/11 are only alike in the fact that people die/died. I would like to turn the question to you -- why SHOULD we mass broadcast a school shooting. Releasing the name of the shooter and in effect "celebrating" them by making them the topic on the news for weeks?