I think the most important thing is to not be one-sided in looking at the issues, problems and possible solutions. I've been a part of three communities hit by (multiple) school shootings, and what's as bad, if not worse, than the horror of the actual event is the rabid fighting and finger pointing that starts immediately upon the first report. It tears me up whenever these things happen because it's not just the vivid memory of what it's like to be "that community", but because you have to brace for the now-routine firestorm that follows. All the while knowing that it's a reaction to the crisis du jour and that the fighting isn't going to get anything done, or do anything for the communities that suffer from violence routinely but never get sympathetic coverage. Violence is built on layers of other violence, and it's not going to be changed by the kind of simple fixes that usually get tossed around.
I've heard a lot of people over the years talk about what should be done without any experience of what it's like to be in those kind of situations, and a lot of it is more fantasy than reality. I know exactly how long it takes me to retrieve a gun from a secured location, ready it and fire with accuracy, and I know that wouldn't be remotely useful in the circumstances I used to face. The only realistic thing I could do was prepare myself to hit the panic button no matter what and scream for those down the hall to run or take cover. The thing that kept me safe from that scenario was a competent and well-funded Threat Assessment team and intervention program, and a lot of the budget makers want to replace that funding with something more ideologically satisfying to their voter base.
I feel like those of us who are called to be peacemakers and problem solvers as part of our mission in the world (however you conceptualize that) need to stay above the reactionary rhetoric. I don't see any one thing, any specific action, that can be done - it's more who you become and the kind of work you do all the time. Get involved in any community action to prevent violence that you can, whether it's mentoring, anti-bullying work, outreach, poverty reduction, mental health advocacy, working between the lines of conflict, etc. See how violence is connected to larger systems or issues, and push for whatever changes are needed. Wherever you work or live or spend most of your time, do a preparedness review for any sort of emergency and figure out the best way you can intervene. Talk across ideological lines to people who will likewise be facing the situation and listen to what they need and what their concerns are in how to respond to emergencies. Get whatever appropriate training results from those conversations and your realistic assessment of your skills to find ways to improve your ability to intervene, in whatever way is right for you. Prepare yourself to deal with worst case scenarios, but be prepared to deal with the fact that no situation will likely go down like you imagine it will.
Frankly, some of the most hopeful solutions on the school shooting issue that I've been a part of have been community dialogues that pulled in law enforcement officers, teachers, parents, and students as community members rather than their usual roles and divisions, and by some miracle got an honest and open conversation - and listening - going about how scary life in the schools had become (even in a so-called "peaceful" town with a crime rate in the lowest quarter of the country's average). People realized that a lot of the real problems were ones that no one wanted to talk about, while the usual conversations that sucked up all the debate energy really had little to do with the main sources of danger.
