Identify a current political issue that affects you and your community.
Educate yourself about the issue by reading at least three articles from reputable news sources about the issue.
Determine which policy-maker is in the best position to represent your interests with respect to that issue. That could be your representative in the U.S. House of Representatives, your representative in a state legislature, or some member of the executive branch. The key is that you identify a person who has some policy-making authority with respect to the issue you have chosen and a person who might listen to your position (for example, choosing your own representative to the U.S. House rather than some other representative).