Adsense is mostly a numbers game. Get more traffic, you'll get more clicks, you'll get more revenue. Topic has a lot to do with how much advertisers are bidding for the keywords as well. The higher the advertisers pay, the more money you make per click.
Don't stop adding fresh new interesting content. No just a "texts for google" site. Think about optimizing the font size, ad formats, even theme. I guess this site may generate 400~800 ip per day now, how to improve it? Look around to find more seo tips.
You can't only rely on "just get more traffic" sometimes. There is one important on-page factor that is unspoken here, which is A/B split testing. You can reorganize different copies of ad placements on different areas of your webpages and test each one over time. You will absolutely find one of those copies that converts the most clicks. After that, create another ad layout and try to beat that record again and again.
Oh, I just remembered: Google has a Website Optimizer (type "Google Website Optimizer" in google to find it. first link.) This allows you to create different website layout easily to split test against each other.
Friend, The adsense best tips is to get yourself registered in various forums across the world and have the good signature and keep posting the valid replies , dont ever tell the visitors to visit your site ,, and is you know the seo , do that also for more visitors to your site .. if you can you can use the traffic exchange sites ,, some of the traffic exchange sites mentioned in my website will be useful to boost your adsense revenues,.. thanks Balaji