They should approach this like the public health problem that it is. Gun control, training of proper gun use, lawsuits against gun manufacturers, lawsuits against those who make the public less safe from guns in some way, mental health awareness education, support systems in the community, suicide prevention, advertising against guns and that culture, movies about the actual real life effects of gun violence, TV shows against gun violence, survivors/victims of gun violence touring schools at various levels, anti-bullying campaigns at every level of education and in communities, etc. A holistic approach coming at the problem from every angle and permeating US society.
I was a gun owner and had a lot of them but sold most of them to get letters out back when we lived in Northern CA. Took them to a Santa Rosa pawn shop. I still have a few left. I grew up in Reno, Nevada where it was normal to have 10 year olds who knew how to use shotguns, rifles, handguns and the like. Lots of hunters and sportsmen in Nevada.
A "friend" shot me in the left pinky with his BB gun and that really killed any attraction I had for hunting and guns back when I was around 14 or 15. He had been aiming it at my eye at that time but I convinced him to try to shoot between my fingers instead. He missed. I found the love of books right after that but became a lot more isolated from these youth. Nevada can be a weird place to grow up.
By the way, Stephen Paddock looks like he came to Nevada late in life.
Stephen Paddock - Wikipedia