Several years ago, during our eBay infancy, we sold a fair amount of trading cards and were pleased with the results. I am sure that we "gave away" some great deals because we were not well versed, so when I decided to sell some more recently, I went "back to school" to learn more.
Ouch, my head hurts and I don't know if I will ever get the finer points down. We thought grading records was detailed but if you have ever looked at some of the grading systems out there for trading cards, it could intimidate you into not selling. http://www.psacard.com/grading/grading_standards.chtml
Professionally graded cards can bring several hundred dollars more than the same exact card that is not graded. Trying to research which ones had much greater value if graded, wore me out, so I guess I am going back to the old standard of providing a good picture and describing the wear, wax deposits, stains etc to the best of my ability and then let it ride.
Hence the beauty of the eBay platform. Folks like me, selling things I really do not know much about, but we still can make a buck. Now before you conclude I am a total loss, I DO know about some things, but not trading cards.
I did not know much about teddy bears until we started selling an inherited collection. I can put teddy bears in my knowledgeable column. Wow! I have two things now!