How can you make a living online?
The key is to NOT try to make a living online. Get an actual job first...salary, benefits....and then work on a website in your spare time. It is incredibly difficult to start a website right now and make enough money to live on just that. If it were that easy, everyone would be doing it.
Sometimes you get it lucky and hit it big, sometimes you don't. But at the end of the day, it's much better knowing you don't have to hit it big to afford things. It always stays a hobby and stays fun.