You can only donate $3500 to any politician. (legally, if you do something illegal and are not caught...). There are complex limits notice when you say something. (for a small city that limit will make them listen, but nothing national or even a large city)
What you can do is get out votes. People knocking on doors is still one of the largest drivers of votes so if you organize those systems they will listen to you.
I am not at all familiar with the US system. How come there is a $3500 donation limit to politicians, but the tech billionaires have donated hundreds of millions to the inauguration fund?
Miriam Adelson donates 10 million to Trump before you get up in the morning, every day.
I donate to the party, and I donate at the individual limit. At that level they still care because people who donate at that level are connected with other people who donate at that level, and those people tend to reach out and coordinate. Periodically I get emails from other donors who ask me to reach out to such and such a person, a candidate or a party rep, and encourage that they take a look at X issue through a particular perspective.
I think more people would benefit from forming Super PACs and using that as leverage in pushing political change with parties.