Fortunately, there are many resources available to help. In addition to the BlogHer events and site, some of my personal favorites for learning tips on writing compelling content, marketing and monetizing are Fizzle.com, MichaelHyatt.com and Problogger.net. All three provide lots of free advice (and more in-depth training and support is available for a fee).
Write down every topic that you are knowledgeable or passionate about. You'll have a much easier time making money from a blog you are interested in, rather than trying to write content you don't like because you think it will make money. Some examples are hobbies that you enjoy, your career, or some specific and miscellaneous knowledge that you have.