I guess a good start would be document gun holders digitally and not on a pile of paper where nobody finds anything and has water damage. Another approach would be not having guns sold in the supermarket. Furthermore, you could ban ads for guns and make it very hard to buy heavy stuff used only in war zone. And lastly restrict who and how weapons are allowed to be transported on man. Of course, one has to have a valid reason to have a weapon on them. Going shopping with a gun out of fear is mot a reason.

First we have to stop bringing new weapons to people, than we can think about collecting

I’m Swiss, we have nearly as many private weapons per household as Americans have, but we have way less shootings, all the things above apply here and I think it kinda works.