There's a very interesting post over at the Digital Point AdSense forum called My 2006 AdSense Summary – From $10/Week to $800/Week that everyone here should read, because it underscores what I've always said in this blog and in my books: passionate quality is the best way for individuals to make money with AdSense.
What do I mean by “passionate quality”? Two things:
- You build sites/blogs around topics that excite and/or interest you. That's the passion part.
- You create original, relevant and useful content for those sites/blogs. That's the quality part.
The downside of this approach is that it's definitely a long-term approach that requires time and effort on your part. Which is not what everyone tells you.
Here's a great tip from the posting:
…Reading diversely doesn’t mean just reading forums, I also highly recommend buying ebooks, books taking classes to extend your learning beyond that of JUST DP – there is a whole world of thinking out there and often I think that so many people are just reading DP thinking that it is a one stop shop for everything.
The reality is DP doesn’t have it all and a $20 book from Amazon on AdSense or SEO could make you thousands of dollars. Let’s face it, if you aren’t willing to part with $20 at bare minimum to extend your expertise, chances are you aren’t going to be the next person here making $XX,XXX/month from anything online. That said there are definitely exceptions to that but it's extremely rare. Plus you can certainly fast track your development and earnings if you are willing to shell out a few dollars to increase your knowledge, or get a good quality design made, or some special feature for your site. Plus if you have invested money into your projects chances are you will be a lot more committed to gaining a return from them which will only further contribute to your development.
Did I mention my new AdSense book is for sale? 
Seriously, a lot of great advice in that posting. Please take the time to read through it all.
Eric Giguere wrote Make Easy Money with Google and Uncommon AdSense. His goal is to get his AdSense blog into Matt Cutts' blogroll.