OK. So again, what is the answer?
1. Allowing gun manufacturers to be liable for manufacturing/design defects in their products, like every other manufacturer of goods in the country
2. Legislated mandatory additional safety features, such as biometric safeties.
3. A sweeping background check reform, centered around the fact that a gun cannot be sold until a person is affirmatively cleared by all interested parties, and assuring that all databases are connected and have redundancies to double-check each other, with flags set up to prohibit sale until all missing/conflicting information is resolved
4. Limits on magazine capacities, and other features which make gun operation more lethal, more quickly.
5. Mandatory reporting of lost/stolen guns
6. Mandatory safe storage requirements
7. Better oversight of gun dealers, and the closing of all sale loopholes (online, unlicensed, private transfers, etc.).
8. A continuous focus on sweeping the streets for illegally obtained/held guns
9. Reform based on limiting access to guns due to mental health concerns
Just as a start.
All of these crackdowns wouldn't be as necessary, had we not let the problem get so out of hand, by being so careless, and so beholden to a terrorist organization for commercial gain. The entire culture surrounding guns needs to change. Celebrating the very few times when someone successfully defends themselves with a gun is part of the culture problem. "We need guns to defend ourselves from guns" is a large part of what got us here. Until this brainwashing is stopped, things won't get better. In order to get that one-in-a-million successful self defense with a gun, you need to allow millions upon millions of folks to arm themselves, creating thousands upon thousands of crimes and (intentional and accidental) deaths in the process. It's stupid. It's morally criminal.
Edit: Those focusing on getting "assault rifles" or "assault weapons" off the streets, as a primary tool to combat gun violence, are a huge part of the problem, too. That will do little to nothing, in the grand scheme of things, and if that reform is implemented (without other, more comprehensive measures), the killing will continue, and gun nuts will be even more empowered, screaming out "See!?! More gun legislation hasn't worked!"