The author is right that the only way to change political agendas is to change the voters' agendas. In some circumstances that just wont mean anything (investingvin infrastructure has huge support, yet is opposed by a significant number of reps and sens). How do you change the minds of people who either dislike firearms or don't care? You have to meet them where THEY are, on their ground, and display understanding of their reasons.
Aside from 2A I'm left of center, that's well known here. I am the highly educated professional whose peers dislike guns. I don't consider myself elite but I would be lumped in with that group at a trump rally. How, then, would you reach someone like me? First, how not to. The "what about 'shall not be infringed' don't you understand?" line is a total waste. People like me can read case law and articles and know that argument is flatout wrong. Coming at me angry and indignant, or with insults like "you don't understand facts and logic" is also a waste. People like me make their livings with facts and logic. They might not have all the facts because they havent had a reason to find them, so share them without acting like that person is an idiot. Getting shouty and spewing that stuff will reinforce the idea that gun people are ignorant, emotional loons who themselves don't know how to reason. Stop wandering into Target in a bunch of body armor with a Punisher patch and your AR slung across your chest. That makes you look like a militia lunatic. At best you're perceived as a reactionary nut, at worst threatening. Either way no one's mind is being changed and no dialogue is being opened.
My suggestion, dump the conspiracy theories and don't act like you know they're all part of some elaborate scheme to subjugate the country. If we start with things like "Nancy Pelosi and Chuck Schumer want to take our guns and make us patriots into communists! Freedom! 1776! MAGA!" we've failed before we've begun. I'd tune you out and write you off immediately if you came at me with that. Find common ground. Statements like "I won't talk to a libtard damnorat." make it adversarial and no one is going to listen to someone spewing that ****. Ask why they're anti 2A and remember that they consider their position just as valid and reasonable as yours and it often is. I've had some success with a calm conversation. I had a physician who hated guns because all she ever saw of them were bullets in bodies. An abdomen destroyed by a bullet is pretty horrible. She saw gun owners as low class, uneducated, dangerous people. She was surprised I own a bunch but softened when I explained that target shooting is very similar to going to the driving range. Eventually she tried a .22 and chilled out a bit. The new experience gave her new perspective.
To sum up, leave the conspiracies and attacks at home, meet people where they are, ask why they hold their opinion, and be measured and reasoned in the discussion. If we're trying to change their opinions we have to connect with them on their turf about their beliefs and present the most reasoned presentation we possibly can. Others may here have other ideas. This is just what's worked for me and what would work with me if someone wanted to change my mind about an issue. If someone on here doesn't care about changing minds then of course they're welcome to disregard the above and do their thing, as they have a right to do.