Practice, my friend. It's easier than you think. A lot of people just pretend they're looking through the book to the floor and just keep turning pages. The words should be unfocused, but not necessarily blurry. Personally, I like them to be a little "soft" but neither blurry nor hard - for this I have to remove my glasses when I PR, but it's worth it.
-Ramon http://razor.ramon.com
