I would like to re-iterate what Pete said. In the beginning I found the long relaxation routine that Paul takes you through to be essential. It really helped me anyways.
But with practice I have found that I don't need to prepare for more then a few seconds to get into state. Over time you get used to what the ideal photoreading state feels like and you can get into it quickly. I crack a book and my eyes want to diverge automatically now.
