You have some good points for your essay.
Here are a few suggestions that might make it better...
First of all, being a volunteer in community brings teenagers an opportunity to know about their living enviroment and get to know their neighbors.
This is a good point you are presenting. This might make it sound better.
Taking part in a community project helps teenagers understand the environment they live in. This is the best way for them to truly find out about their neighborhood.they may required to organized some community activites to promote the communication between neighbors, teenagers learn about how to organize an activity or organization.
They will understand how to organize a project or activity successfully by taking part in community projects.Teenagers can learn more about the problem of homelessness and way they can help them, as well as gain perspective on life by helping people in need.
Teenagers will learn about the homeless people and ways to help them. This will enrich their character as well.You have very good points for your essay. Try to correct the small grammatical errors and you will have done a good job.
:)