I think we're all still trying to deal with the enormity of one young man, with who knows what problems, killing himself, his mother, a school principal and teachers, and a lot of random small children who never did him any harm.
I know there's a tendency for us to want to change something as a society, to make sure something like this never happens again. But what? Opinions differ on whether or how to limit the availability of guns; we all wish that more could be done for the mentally ill (assuming the shooter was ill), but it's difficult to know what. Taken to extremes, the actions we take could well reduce personal freedom without any guarantee that they will have the desired effect. It's not even clear, in the end, that society as a whole will take any action at all.
Where does that leave us? Are we, as individuals, powerless unless we can persuade a large enough percentage of our fellows to take the same action?
Not at all. Even if indirectly, we have at our disposal every day the opportunity to take action. Look out for the defenseless, the children, the mentally ill. Surround them with your love; buffer them from danger; comfort them when they're hurt.
That's an action anyone can do, that has no potential for harm, that needs no negotiation or legislation, that leads by example.
Who knows how many shootings have already been prevented by just such actions as these.