Some links on how to see stereoscopic photography if you're having problems: here, here (these are parallel), and here. I find that it helps, as the two blurry images get close together, to pick out a distinctive feature you can make out in both and concentrate only on that.
One tip that might really improve my photography is the One in Thirty Rule, that the pictures should be taken at a distance apart equal to 1/30th the distance to the object being photographed. I tried to keep it about the distance apart my eyes are, which is much further apart than 1/30, probably more on the lines 1/4. This may explain why some of the accidental ones work much better than several of the intentional ones.
Hey, a website devoted to stereoscopic photography!