Some of the things to look for range from basic information to a more detailed inspection of the checks, credit cards, type of identification used, etc., in order to detect credit card abuse and/or forgery.

• Does the check presented have a perforated edge on one or more sides? (Showing it has been taken from a standard personal checkbook or company check log).
• What is the check number (is it low, indicating a "new account")? Is it a high number, indicating an older established account? (Note: just because it is a high number doesn't necessarily mean the account is "old" or "established."  It is just a possible indicator).
• Do the signatures match on the check and the identification presented?
• Do the checks appear to be altered or have signs of erasure, mismatched type, etc.?
• Is the numerical amount of the check and the written amount of the check the same? Is it dated correctly and is it signed?
• Is the check written on a familiar bank? Is the bank local or out of town?
• What is your policy on accepting checks for more than the amount of purchase? Does it need a review?
• What is your policy on cashing payroll and/or two party checks? Does it need a review? These types of checks can be trouble under certain circumstances.
• Look for obvious signs of tampering on credit cards such as erasures to signature lines on the back, double or re-stamped characters on name and number embossments.
• Many cards have holograms.  Is it the symbol that goes with that company's card? Has the hologram been tampered with, added on, etc.
• What is your policy on asking for photo I.D. along with the credit card (even if the card has a photo on it)?  Verify the person with the card is who they say they are.
• Use common sense.  Do things "add up"? For instance, if the credit card is in the name of Dr. John Smith and the person presenting it is a 17 year old girl would you question the presentation of this card? (Note: the 17 year old could very well be an authorized user/holder of this card.  Review your policy on this type situation).
• Look at the magnetic stripe on the back of the card.  Has it been deliberately scratched, marred, partially removed, or is it otherwise defective (possibly demagnetized)? Keep in mind, the strip is encoded with information and can be accidentally damaged (and innocently so,) however,  criminals often do this in order to prevent normal "checking" of the information through electronic means. This forces the "check" to be done by phone or the old fall back, the printed list of stolen/lost cards, so if it is a recent stolen/lost card it may not be on the list yet. If the name or numbers on the card have been altered, the same may be true. 
• Then there are the criminals that will present these cards during very busy times or to the obviously frustrated or new employee that will not take the time to go through various procedures to properly get "authorization". This method is used with processing checks properly.