I introduced a 300x250 AdSense rectangle into the top left of my blog posts and almost doubled my eCPMs. I was really glad I finally did it, but was kicking myself that I hadn't done it sooner!
- Increase your traffic. Get good SERP position will drive more traffic to your site. - Change your ads display, position, color, etc
There is no way to increase your Adsense earnings overnight... without cheating. If there was such a way everyone would be doing it. Google only accepts clicks from the natural flow of traffic through sites. Anything else, is risky. If a publisher really needed to boost their Adsense earnings... quickly, they might try and use subtle forms of Adsense arbitrage. But this can also get a publisher banned from the Adsense scheme. Basically it all depends on your level of desperation and how much risk you are willing to take.
I think there is almost no way of doing it overnight. Unless you get massive exposure (marketing, banners and stuff). Not even changing colors or position has, in experience, made much change.
I do not believe anything substantial change would take place overnight, you may see some spikes, but it will fizzle out ..
Index your site in Google, Bing and Yahoo and wait for the coming traffic from these major search engines, this is the best traffic for Adsense from my experience!
don't try asking your friends..that's not a good idea..i tried that before and i got banned. If you want your friends to help, just to them to click the ads once..hehe