Maybe the Dems need to emphasize suburban issues like gun control more often. The vast majority of people live in the suburbs, and those who don't want to. You can't escape it.
I can't imagine that emphasising gun control is going to help in the suburbs more than it will hurt in blue collar, working-class district. I can't see many suburban GOP people switching over based on gun control.
I don't think a lot of these people are GOP people so to speak, they are more like independents or weak identifiers, maybe even Democrats who voted Republican once in a while based on taxes. What the Dems need to do is (locally) emphasize the issue. It's one more thing to talk about other than just economics.
Why? Gun control, as an issue, is dead in the Democratic party. How many candidates won this year in red districts who emphasized gun control?
Besides, gun control is just silly. If you take away the guns, then the criminals will still get to them, and honest law-abiding citizens will be defenseless. Even if criminals somehow can't get their hands on a gun, they would just use another weapon.
A lot of Dem candidates in red states have been doomed because of the NRA. The Coalition for Gun Control is not as effective.