Produce unique, useful content - and viewers will come. This will, in turn, increase your ad views and clicks.
if you made a lot of posts in your Blog and indexed your blog with Google webmaster tools than it will be possible to earn more from ADs. have a look for that site :- http://www.youtube.com/user/InsideAdSense it will help you better to now more tricks about Google.
More traffic is required for your blog. Make some arrangement for your blog in various types of Search Engine Options. Make some important news so that people come daily to your blog.
Traffic is all the important ingredient for a good revenue, even u have high pr with no traffic u can't make a revenue out of it
I would say make sure you are having good content but also coded correctly in xhtml validated. But at the same time its all about the traffic and content, you have to be offering the people something new that they havent seen around.
Have good content with plenty of links pointing to it from other sites. Try article marketing and directory submissions, but don't expect anything overnight.