I think Australia has done a masterful job with their gun laws. I'm sure they're are some exceptions or imperfections, but that's always going to happen.
Absent that, there are some people in our society who shouldn't own guns. Felons, domestic abusers, people on the "no fly" list, the mentally ill, etc. I don't know why we can't ban these people from owning guns, with a judicial process of some kind where, if they've shown themselves to be good law abiding citizens for some long length of time, they can get their gun owning rights back.
An FBI or ATF universal background check with no loopholes. Bump stocks banned. And I believe assault weapons should be banned too. They're military weapons for mass killings. Plus, large magazines should be illegal. Pick a size, I don't know, I'm not a expert.
As I've said previously, the children/millenials who have grown up with the mass killings will hopefully come to power through elections in Congress and the Presidency and hopefully change things for the better. We just have to wait for the old white men backed by the NRA to retire, die, or lose elections.