In-depth tutorials are great for getting links and social shares. However, they can also be a great way to earn money on your blog. There are a number of ways you can make this happen - include affiliate links for the products you use in your tutorial; promote your own products in the tutorial; write a tutorial to promote an advertiser's product (just be clear that it's a sponsored post), etc.
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.
Once you setup your account on AdSense you will be given a code to add to your blog. This code will automatically display advertisements on your blog from companies who are part of Google’s advertising network. You may see ads from small companies related to your topic, or you may see ads from large companies that are completely unrelated to your topic.