However, letting your eyes relax and focus behind an image is a skill that has to be learned. Most folks can learn the trick, but some never quite get the knack. It took me almost 6 months before I was able to learn the trick. The good new is that once you learn it, it becomes very easy to repeat any time you want.

Teaching folks how to view stereograms is all about teaching them how to focus their eyes beyond the computer screen. The following suggestions usually help:

Reflection
The most common helpful hint for viewing stereograms is to focus on your reflection in the computer screen. You may need to put a light beside the screen to help create the refleciton.

Guide Dots
Many stereograms are created with two dots near the bottom of the image. By letting your eyes relax you can begin to see a third, floating dot between the two dots. When you've gotten the third dot to appear, you should be able to see the 3D content of when you shift your focus to the stereogram

Distance Focus
Throughout most of the day your eyes are focussing on the objects you look at. This involves focussing/converging both eyes on the same object. The closer the object is to your nose, the move the eyes converge and you can feel the muscles in the eyes contracting/straining to hold the focus.

Conversely, when you look at an object a long ways off, the eyes diverge (move apart). This is the most relaxed position for the eyes and is the way in which you want to view a stereogram - relaxing the eyes so that their focus is off in the distance. When the distant focus is achieved, with the stereogram in front of the eyes, the 3D content will be visible.

Note: Most stereograms can also be viewed by crossing your eyes - converging them to focus as though looking at a very close object. If viewed in this way a stereogram will reverse itself. Surfaces which look far away when viewed with a distant focus will look very close when viewed with a very short focus distanced.