So one of the theories is that rumination (sort of rethinking things) causes hallucinations...I've found it best to be actively working or playing rather than quietly thinking about stuff. In my case the voices were pretty much talking about what I was doing and trying to assist in making me do it better so I didn't really have to ignore them it was more like a a team effort...as far as blocking here is a link and there is a part on coping strategies in one of the responses...

http://forums.psychcentral.com/schiz...cinations.html