In short if you want to have less violence involving guns in a select society then you stop the availability to own guns within that given population.
There is a lot of practical evidence to support that assertion in other countries. ie. Japan, UK, Canada who have high restriction levels.
The foreboding problems is how do you implement that in a society where gun ownership is a deeply ingrained law from out the legal constitution that created and formulated that very country ?
The answer to that might creating new laws that overrides those old formulated laws.
To start that withdrawal, an all out ban on certain Assault rifles would be a good starting point.