What is wrong with the following outline? When teenagers give community service, they not only benefit the community, but themselves.
Community service fulfills special needs in the community that might otherwise be neglected.
Volunteers often provide the only companionship that some of the elderly or disabled have because many people in nursing homes do not have family nearby.
Big Brother/Big Sister programs offer kids opportunities to learn, play, and socialize, which they would not otherwise have because of working parents.
Teenagers who perform community service benefit from the knowledge that they are making a difference.
Teenagers involved in neighborhood clean-up programs can see the tangible evidence of how the clean streets and parks improve the community.
Teenage volunteers at food banks and soup kitchens are able to focus on the needs of others and see how they can fulfill those needs.
Many teenagers do not volunteer because they don't know how to get involved.
There are many resources that can help you find a service that's right for you.
The Internet is a great way to search for community service opportunities.
Your local community center or public library can be a good resource.
Ask teachers or parents how you can get involved.

There aren't enough main points.
There's nothing wrong with the outline.
There aren't enough subpoints for each main point.
There aren't enough supports for each subpoint.