Share your knowledge. While a story about your mother pretending to cross the Saharan desert in your sandbox might be a great story, it would probably be difficult to sell as a young writer. Instead, choose to share experiences that relate specifically to areas of knowledge that you posses.
Tell your hard lessons. Those things that you learned by loss of blood and tissue, loss of money, loss of sleep or loss of peace will make for some great service-oriented writing. Perhaps your reader will be wise enough or fortunate enough to benefit from your pain, avoiding some hard paths.
Encourage others through your writing. Everyone has suffered through a trauma or a loss. When you are on the other end of your trauma, use it as a tool to teach others. Write a service-oriented article about how you coped, and give your readers advice on how to do the same.