You can write anything you set your heart to except sexually explicit stories because they are against the site rules and could even get your account banned if you continue writing them.  Write what you enjoy writing. If you write about something that you enjoy, your audience will see that, and you'll have a better chance of people liking your writings. Make your writing engaging to the readers. Be sure to know that what you write is real, begin with a statistic that shocks, and make revisions and edits to your writing. Doing these things will grab the reader's attention. Try asking other people for advice on how you can improve your writings. Doing this will help you become a better writer. Post one saying that you're new like "Hi, Quotev users! I am (your name) and I love to write! Check out my story!" Doing this will especially place your story down on the lower list because everyone does them. If you want to become a popular writer come up with something original. Avoid cliches like "I'm pregnant." or "I cheated on you." Or even "They kidnapped me and beat me, but I'm in love with them." Everyone hates reading stories like that because they have been done so many times. It just gets boring actually, so come up with a story about your personality and make it original. Honestly though, Quotev thrives off clichéd stories. You can be original, or you could churn out the same storyline every twelve year old on the site's been using. Sadly the latter will earn more fans, so it really lies in what your priorities are - do you want readers, or to write stories you care about while running the risk of them going unnoticed? Sharing your writings outside of Quotev is a good way to attract more readers, and thus will boost your popularity as a Quotev author.  Provide a link to your writings so others can read them. Keep updating even if you don't have many readers. Make posts frequently and reply to comments swiftly. Thank your readers often. You definitely shouldn't let your readers control your schedule. Your writing should be a fun hobby, not another assignment. Remind them firmly that you do, in fact, have a life outside of working for them. You can't just disappear for three weeks when you have left a cliffhanger. This is not to say that you can't disappear. Your readers get that you have a personal life. It is just that you have to prepare them first. 
Start writing material. Post some funny/inspiring R.A's. Do not write cliches. Share your writings on other sites, such as Facebook, Twitter, and online forums. Be an active updater. Share your stories in the "Share your story" section in Groups.