I already do things like you mention... walk most places, reuse/repair when feasible, buying less packaged food, avoiding leisure flying (I used to travel often)... but individual impact is fairly minimal, so I've been putting more effort into supporting local political candidates who prioritize the climate.

I also complain a lot at community meetings for new development in my immediate area (things like reducing parking in new buildings, including bike storage, EV charging, better public transit infrastructure)... I've found some of this stuff more fulfilling in that the impact tends to extend beyond what I'd be capable of doing alone... sometimes it's fruitless, but sometimes it works.

I'm trying to skip politics because I think it's fluff and too laggy. But I'm still at theory level. Ideally I'd find a few open warehouses to set up stuff. Tools, materials, gather smart / knowledgeable people, teach and viral spread the new habits. Hopefully it will cost next to nothing and happen faster than politically impeded initiatives.