Parking lot cent? Cent that was dug up by someone with their metal detector exhibiting environmental damage? Steve
Read. Lots! Buy a copy of the Red Book. https://www.whitman.com/store/Inventory/Browse/2017-Red-Books-and-Blue-Books Also available at booksellers and coin shops. (Don't pay too much attention to values published in the Red Book, they are always outdated and for the most part, run high.)
Set yourself on a course to learn what can and can't happen before a coin leaves the Mint. The most important skill in identifying worthy error coins is knowing how they're made and what good ones look like. It's far too much for one post, of course, but it's still a lot easier than trying to memorize a large spectrum of different errors, some of which would closely resemble damage if you didn't already know the Mint couldn't have made them.
@Uniquemarie21 you can pick up an older, used copy of The Red Book for little or nothing-(used book store, Amazon.com, eBay, etc.); although the values aren't important you can still mine a lot of information. Steve
The same way you find a great mate! You've got to kiss a lot of toads before you find a prince. Chris
Easy question. Look at a LOT of coins. The great ones will become obvious. If you're asking about "rare" coins or "coins which are worth more than their Face Value", then you just need to do your own investigative work which would include reading and participating in the bazillions of coin forums that exist out here in "Bit-Land". No two people will value a coin the same as what's valuable to one may not interest the other.
