First you will need to decide what topic to write about. Depending on your interests, your opinions, your beliefs, and the nature of your community, there are many potential topics for an essay like this one.
Here are some practical issues that have ramifications for the ecology, the economy, health or class issues:
Transportation: The presence of public transit can help to reduce costs for individuals, lower a community's use of fossil fuels (gasoline), and make transportation for work more possible for people of all classes. If you community already has public transportation, a secondary issue in this vein is promoting increased use of public transit.
Medical Care: Free clinics can save a community money by allowing people to get regular check ups. Clinics offer a chance at prevention, which is often cheaper and easier than curing a disease or condition that has fully developed.
Free clinics can also help to bridge a care gap driven by means and access to medical services.
...while the United States leads in the development of health care technology, not everyone pays for it or receives it.
Once you choose a topic, your thesis statement should include 1) the identity of the problem you will be writing about and 2) a brief statement regarding the solution.
In our community, where public transit is readily available, a public marketing campaign could help to increase patronage on the transit system, raising the efficiency and emphasizing the benefits of this system in our community.
There are many topics and issues to choose from for an essay like this. Whatever topic you do choose, make sure to include the problem and a brief overview of the solution in your thesis.