Generally when looking for adsense alternatives I look at other reviews other people have written about the company and so on.. In my opinion Google is still king as they have a decent sized client base already and some of these sites don't have paying advertisers for a wide range of areas.
i have yet to even sign up any of my sites with Adsense (ie how much content is needed if I have little to no traffic??!) but there seems with Adsense to be a lot of people that barely make any money and a few people that make a ton of money. It is not clear to me yet how to be in that latter group.
You have to first create a website with content and get it approved by google (they will normally check your website in 24 hours). Then they will allow you to get your code and then all you need to do is add the code and your away.
The amount of money you make depends on your site and the area your focusing it around. Along with that it depends on how many people are bidding on keywords that your site uses (so it's constantly changing).. some people say the number of ads displayed on your site affects your earnings..but I'm not entirely sure in that area.
ok so as i understand it then ideally you want to have a site that focuses on something that is very popular with searches but few sites developed around it.