Seeing the blip page is about seeing with parallel vision. Softening your gaze and looking through the book.
Initally while you are learning it is a bit more difficult to see the blip page and even if you do it seems to disappear. This is simply because we are used to pulling our eyes into hard focus. For this reason it is easier to concentrate on the imaginary X technique when starting out.
On page 48 of the book next to the Einstein jogging (No Blip...) it explains the what the purpose of photofocus is and the imaginary X technique in the following paragraph.
If you've searched the forum you've probably already discovered this link
http://www.vision3d.com/3views.html
I find that it gives the best ways to develope divergant gaze (or parallel vision). It also has some 3D stereograms to practice on. I personally found this easier and faster than just looking for the blip page in a book.
Alex