I don't think you can tell other than by being very familiar with the various sets, and knowing the rarity ..... just like an antiques expert knows the value of particular types of object.
Rarity of a given card is determined by how big a proportion of the whole set was printed in the design of that particular card.
Part of the mystique of such collections is that is not obvious at a glance which ones are common and which are rare. But if you start collecting a set you soon get used to the common ones.
I understand that RarityGuide.com deduces its rarity values by monitoring the trading values on sites like eBay.
Nobody is going to pay big money for the common ones, but some people will pay a fortune for the very rare last card that completes their collection - and that expensive purchase is what defines the rarity value.
Also, if you happen to find a rare one and take it home with you, you will soon get to know about it as they are very highly prized among the undead. ..... so you will be subjected to an almost immediate large scale Zombie attack.
Thanks, but i was wondering how to pick up a card and know if its uncommon or not. What should I look for to tell?
Have a look at RarityGuide.com at:
Best wishes - Majikthise.