If you want to be famous or reach a wide audience, you will have to choose something slightly broader and work hard to make the best content for that topic. A subtopic relating to fitness, finance, or relationship advice is likely to reach the most people. Consider specific but broadly applicable topics such as managing money in college, or a marriage counseling blog.
Most bloggers actually welcome the advance to create great content for their platform. So you shouldn’t be shy in at least trying. There’s no harm in trying. If you succeed, then it will be a big win. If not, continue to network and add value on your own, and eventually, as you build it, they will most certainly come. Just don’t expect it to happen quickly or easily.
Working with advertising networks isn’t your only option when it comes to selling ads. If you end up with enough traffic, advertisers may come directly to you and ask you to place their ad on your site. You can also contact advertisers yourself. The biggest difference from the above mentioned option is that there is no middle man, which means you can set your own ad rates.