Other than being alert to the dangers of "sickos" living nearby, there is little we can do to stop the mass killings.
A radical change is needed in our thinking about guns and the rules governing the handling of them, that is obvious.
Meanwhile, we can be sensible, and let me suggest three ways.
First - we can support civic leaders at all levels who hold sane ideas about guns but more importantly, about how to live together peacefully and in supportive ways.
Secondly - we must be strong supporters of justice, peace and equality achieved through peaceful means, like at the ballot box, in mature discussion, and by being flexible enough to assimilate new ideas.
Finally, individually, we can be persons of peace and good will by being even-tempered, avoiding volatile language and, in general, loving life and other human beings, especially children.