I think you have many ad units and you could work a bit more on blending. what is your traffic source?
The ecpm is important apart from the ctr. Create a niche that pays you more. Many of the common niches will fetch you at the most 10 cents per click. That's not good.
I've had my site for 5 days and already average about 1 dollar a day since the second day. I'm a beginner to tell the truth I don't know what pr is or anything but I get a bit of visitors..I'm waitin to see the secrets myself...