Get involved in the cities government by volunteering, or serving on a city commission. Just start showing up to city council meetings and start learning what is going on and who the players are. You’ll figure out a way to help there.
Just showing up has an impact. I guarantee that simply being present will change everyone's behavior. Most meetings most of the time have no audience. If you keep showing up, you'll eventually figure out what's what.
My next piece of advice is to get on your representative's calendar. Pick an issue, any issue. No matter how small. Like fixing potholes or improving a road crossing. State the problem, propose a solution, make an ask, be cordial. 5 minutes. Then do it again. You likely won't "win" at first. Tenacious wins in the long run. At some point, politicians will do what you ask, just to make you go away.
I guarantee that there's a local issue, the more local the better, that you care about, that needs your attention. Anything and everything you can imagine is on the agenda at some point during the year.
Seconding the 'go to city council meetings.' Hearing first hand what goes on there will be helpful, and depending on the format, you can directly speak on issues you care about.
