Target on user created contents

Know your limitations, If you are maintaining more than 20 blogs/sites,you cannot post enough keyword rich articles on each and every sites/blogs. So just share that 'task' to your readers. Let them add contents for you.

Start web directories like http://www.companiescontacts.com/ and invite your readers to add their businesses for you.

Increase your adsense earnings

1. "Lesser the ad blocks better the click thru rate",this is true for every situation.You may need to limit your AdSense blocks to only one (maximum 2) per webpage when running AdSense ads on your site.remember by running multiple blocks per page you will have lower paying ads placed on your site which will decrease your earning

2. Place your ad blocks just under your post heading ,this will help to increase click thru rate.Use large rectangle blocks to attract the visitors eye.

3. Make sure your website is constantly updated. You can incorporate RSS feed on your website so that fresh contents from news sites would appear on them.this will help you to show fresh content on your website.

4. Try to use high paying keyword but never use "too high paying" keywords,use moderately paying key words

5. Try to blend your ads with the website content.

6. Make your AdSense ads similar to your website layout but never try to force your visitors to click these ads, your account will probably get banned by Google.