Volunteer with your preferred local political party. The path to getting into politics can start as easily as showing up until people know you, and having good ideas that enough people agree with. Your job as a politician would be to carry those ideas to the structures of power (town council, school board, whatever).

It's pretty time-consuming, but it's a big responsibility, making decisions that affect lots of people's lives. So, trade-offs.

Another reason not to do so is that it's a high-risk, low-reward endeavor.