Don't sacrifice morals for a quick buck — At the outset, you'll want to do all sorts of things to make money online, but don't sacrifice your morals for a quick buck. Not only will you put people off, but you'll lose Google's trust. You also shouldn't concern yourself with things like Adsense or other ads on a blog before you have around 100,000 visitors per day. Yes, per day.
If you have experience with marketing, SEO, or a knack for getting people excited about the products and services you use on a regular basis, think about refining your skills and putting them to work making money online as a small business marketing consultant in your region—especially if you can become a local SEO expert and can help local clients rank higher in their search results.