"DIVERSIFICATION! That concept cannot be stressed enough for 99% of AdSense publishers. I've been a publisher for about a year now and the one constant I've seen throughout is that those with many sites on different topics don't have nearly the huge revenue swings that others who have only one big site do.
The other important concept is to keep adding quality content and putting the AdSense JS on those pages. Look, you can hope for higher pay-outs per click, or you can ignore that entirely and just keep on keeping on (adding more pages). Put your nose to the grindstone and write (or pay others to write for you). PUBLISH!
Think of it as planting seeds. Each page of quality content that you add is a flower ready to bloom in a few weeks or months. Follow all the Google rules and keep adding content!
I've gone from nothing to a steady monthly increase by following this simple model. Build pages around keywords that get a decent number of searches at the engines, plant those seeds (publish!), and stop pulling out your hair over the statistics." Swebbie
