Believe me, it can be just as hard to tell when you're eyeball to eyeball with it.
We've tried to combat this problem by using arrows, text on the image and sometimes ridiculously detailed (but hopefully vivid) descriptions. Dr. Bakker's just sent an image that helps make the leap from just-a-rock to living creature:

This Dimetrodon toe bone was discovered in the plaster jacket the team brought back from the site. The jacket is being excavated at The Woodlands Xploration Station.
Another image of the Dimetrodon toe bone, which gives it's specific size. From this, you can imagine how large the entire foot would be, as well as the full animal.
They've also uncovered what looks like another full fin spine. Since they are digging from the bottom of the layer towards what was the surface, it's a very nice surprise to find so many associated fossils.

You can see the spine running along the bottom of this image, parallel to the measuring tape. To the right of the image, the spine looks as though it continues under the dirt. Continued excavation with help determine how much of this spine has been preserved.
Technorati tags: museum, fossil, paleontology