They say that you can’t really tell much about a reed by the way it looks. I think that is true, however looks do play a small part in how the reed functions.
The most important thing when looking at a reed is symmetry. Both blades must look the same. If your reed is not vibrating correctly, check and make sure there are no obvious mistakes or thick pieces of cane in strange spots.
When you “crow” the reed, make sure it is a “C”, and then you can think about balancing the reed.
Below are some pictures that I took of some reeds for the “Making Oboe Reeds” book. Just click on each image to see a larger picture of it.