how i can earn more from google adsense?

What you are suggesting is not illegal, it's just against Google's terms and conditions, and the email bit sounds a bit like spamming, I'm afraid. Concentrate your efforts, all of them, on making your site so good that people want to visit without being asked, like they do at digg.com, plentyoffish.com and flickr - all sites that make money from Adsense

I have a few sites. My friends visit them regularly but none of them ever click the adsense ads. I don't ask them to and they don't. If you decided to disobey Google's rules, it's hardly likely that your friends would take time out to visit your site and start clicking. They probably have more important things to do anyway.

google adsense is placing the relevant ads on your web/blogger. if you allow to place the relevant ads that are generated by google automatically , you will be able to earn money on click basis and so on.

currently, i am using this concept. and it is interesting.

you have to do nothing. The simple thing you have to do is just in your browser type www.google.com/adsense

and later sign up for account.

my blogger is www.india24hours.blogspot.com

NO. it's just against Google's terms and conditions, on making your site so good that people want to visit without being asked, like they do at - birthdaypartyideas.com ,greenwichmeantime.com