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.
Watch out for inflation chipping away at your assets. We've all heard an elderly person describe the purchasing power of a coin in their day. Inflation continues to make today's money worth less in the future. To win the race against time and inflation, learn to invest your money in the right places. A savings account might help you to keep up with inflation; however, to stay ahead of the game you'll want to invest in bonds, stocks, or some other investment that returns above the average rate of inflation (currently 3%-4%).
One of the cool things about Google AdSense is that it's so easy to get set up. If you have a blog or website, you can sign up for a free Google AdSense Account. From there, Google will give you a unique code that you will paste onto your website. Google takes it from there, tracking your page views, traffic, and earnings on your behalf. There is no upkeep or maintenance to get this thing going, which makes it a no-brainer if you have a website already.