Proper colour blending can help. Ad placement can also help. Having said that you should also be aware that many people will not click ads simply because they are not interested in what is being peddled. I surf with javascript turned off so I don't even see ads. Every now and then I turn it on and this is what turns me off with respect to ads - sites/blogs plastered with ridiculous ads. Some blogs have more ads than content. I leave these type of sites just as quickly as I arrived and never return. Something to think about.
