How I make 15K a month at AdSense
I start with keyword lists from adsenseheaven dot com which guesstimates the most expensive keywords to bid on in the PPC AdWords side of the Google ad world. I generally ignore the top 1000, as they are very competitive and saturated. I am not concerned with the top payouts.
I store this data every month in a mySQL database with the previous months data, and over time I am able to see which phrases are consistently in the lists and unlikely to disappear. I call them long term performers.
I cross check each phrase with the number of pages currently indexed in google, to see how much competition there is for a each key phrase. It's usually easier to land a top 10 first page SERP position if there is less competition for the phrase.
A story of Success
I've been really into SEO and interlinking my own network of sites to get high rankings in the SERPS for the past year, and experimenting with different types of linking strategies, automation of content creation, and building up decent revenue with AdSense and affiliate offer marketing through search engines and Social Media.
Well, my network included about 20 sites when this picture was taken, each making about 2-15 dollars a day. That was April. Now, I've obtained about 100 sites, all feeding link juice to each other on seperate IPs and hosting. This drives mad traffic and I currently make a few hundred dollars to nearly 1000 (peak traffic) a day from this small network.
I maybe spent $2000 on this tops, but you can start out with 10 dollars for a domain and cheap hosting. Once you start building your network, just gotta keep making it bigger with better links and what not. If you can pay for something to automate most of it, do it and you'll save a lot of time and make a ton more money.
I leverage the traffic with cheap search traffic, too, and run affiliate offers through landing pages which bring me at least a few thousand a day now, too. It took a while to set everything up and realize what I was doing, but I'm glad I sat down and just decided to do it rather than care about whether or not my accounting homework gets turned in on time instead. Now, my college mates are all asking me to teach them in class instead of the boring marketing teacher. Lol..