http://www.reddit.com/r/IAmA/comments/ljioz/im_16_and_i_make_40day_consistently_with_google/c2t73l4
I'll let this be the comment I link to for the "How?" questions.
Basically, what I learned to do is to make a site on something you're interested in. It has to be a really focused niche, if its broad to any extent you'll have trouble getting good keyword rankings in Google, which will account for 80% of your traffic.
Your site should be at least 50 pages to start, and update from time to time. You'll need to learn HTML and CSS to make a site design-wise, but I recommend learning basic PHP for functionality purposes.
From there, put it all together and hopefully you have a good looking, informative, and functional site. Promoting this is the hardest part. Make YouTube videos, post your link everywhere without being spammy. Guest blog on large sites in your overall niche. There are tons of ways to promote, but what I've found is that as long as your site has good content and you're mindful of good SEO practices, you should be doing quite well within a matter of months (starts very slow). On to the next site then!
