Offering a solution to a problem takes effort.
What is your plan?
Some ideas.
The easy one, copy whatever every developed nation is doing where they get much better results than we do. That might be untenable since our Constitution guarantees it as a right and not a privilege.
The more difficult ones;
Universal background checks.
In addition to domestic violence there's a number of other crimes that are strong predictors of violent behavior, like excessive cruelty to animals. Make those convicted of these crimes ineligible to buy a firearm.
Raise the age to buy any firearm to 21.
Ban assault style weapons like the AR-15(I don't know if that would help).
3 day waiting periods for any gun(I also don't know how much that helps).
Fund the CDC to study gun violence.
These school shooters tend to visit websites where they idolize other school shooters. Get the FBI to monitor those sites.
Make it mandatory to secure your guns with a lock(this might already be a law).
Put a tax on guns and use it to fund ad campaigns for basic gun safety.
Modify future designs of schools in such a way that makes mass shootings more difficult.
I really don't think arming teachers is a good ideas just because teaching is its own profession and being a SWAT officer is its own profession and there's so little overlap between the two that I don't there'd be enough of them to do any good. It's a policy that's more likely to increase the incidents of careless idiots leaving guns in their desks.
A lot of the talk I'm hearing out of the powers that be seem to be focusing on just school shootings. It's like they forgot about the Vegas massacre and that Texas church massacre.