Gozel,
You don't see an X for real. Just relax your gaze to widen itself to see all 4 corners of the pages at one time. That's it. And as allenhm says---just look over the middle of the book a little and the blip comes into focus naturally.
Hold a book open at a 45 degree angle so that you have room to look beyond the center to about 3 feet in front of you. That'll do it.
Look at something directly in your room. Now just relax your gaze to widen and w/o moving your eyes see more. Periphereal vision. Look up that definition.
Definitely put a slight smile on your face. Really, it helps to relax all your facial muscles. It truly makes a difference. It's a seamless kind of thing. So simple yet so effective that you wonder why we don't do it naturally. Probably as children we did. Reading and smiling and having fun. 
