Think about things that you care about. Whether that's politics, or fashion, or music, or literature, or goings-on in your city, or even just the goings on of your day-to-day life. Even if you do write about high school and being single, there's bound to be someone out there that can relate.
And if you don't want to write about that for your own reasons, then find something else that interests you. No matter what it is, Mibba is a big place--someone's bound to share your interests. =)