A partial solution would be soundproof houses, though that doesn't rescue one's backyard or park from loud neighbors. Every house or apartment should have at least a room or two that are impervious to outdoor noise.
At the same time, there are really good reasons to make noise sometimes, from music to machines, so better ways to do that without overly bothering others are needed too.
This, at least in America, is the real heart of the problem. Our building practices have leaned so cheap for so long on thin margins, that walls, even exterior, are paper thin to the point of being ridiculous.
This becomes much more obvious if you have travelled around to other countries, and it's not all about wealth. Yes, rich ones such as Switzerland are a great example because of the heat containment requirements they have, there are poorer countries that still know how to build a house without sound going through it as if it was nothing.
This doesn't mean noise pollution shouldn't be tackled itself, but cities are noisey, and people at least deserve to have domiciles that give them a refuge.
This means you need to start participating in your city and county governments if you really want change (like many things!)
I've spent serious time looking into this. One of the biggest sources of noise is windows or other places air can start to get in. I re-sealed my windows as best I could, but it's still a crisis of sound. Windows that claim to be sound-isolating either don't open at all or are very expensive to buy or properly install.
But: These are the kinds of "nobody cares it's your fault it bugs you and you need to find a solution" comments that are pervasive. Sure, I need to do my part as someone who's bothered by the sound, but there is no real incentive for the producer of the noise to cut it out.
Not singling you out in particular, just showing that even honest proposals for solutions tend to miss the elephant in the room: noise pollution that isn't pure sustained decibels can still be damaging.
Say I have an obnoxious horn that is a few db below the ordinance/limit. Many may claim that's a nuisance although somehow the blower isn't. But why shouldn't I get to play with my horn for a few hours every day? Maybe my leaves don't like it. The fact that the leaf-blower sound comes from doing a "chore" seems to change the equation in ways that are hard to articulate.
These are the kinds of "nobody cares it's your fault it bugs you and you need to find a solution" comments that are pervasive.
If I came across that way it wasn't intentional. I actually really, really hate unwelcome sound/noise, but I'm also a night owl so I can't really enjoy many of the things I want to enjoy because it would bother others.
Realistically we all make noise in ways we might not initially realize, so on top of singling out and improving the outliers like car horns and yard equipment, we also have to consider ways to let us all go about our business more quietly, and to find solace from noise.
At the same time, there are really good reasons to make noise sometimes, from music to machines, so better ways to do that without overly bothering others are needed too.