• "Lapping" - this scheme involves temporary withholding of receipts such as payments on accounts receivable. This is a continuing process which starts with a small amount but can run into thousands of dollars before its detected. For example, an employee holds out a $100 cash payment made by customer 'A' on March 1. To avoid arousing suspicion on 'A's part, $100 is then taken from a $200 payment made by customer 'B' on March 4. This is then sent on for processing and crediting to account 'A'. The embezzler then pockets the remaining $100 which increases the shortage to $200. As this progresses the employee makes away with increasingly larger amounts of money involving more and more accounts and it can take years to detect. Any indication that an employee is keeping personal records of business transactions outside of regular books for accounts should be looked into immediately.
• "Check Kiting" - the embezzler here must be in the position to write checks on and make deposits in two or more bank accounts. One account may be the embezzler's personal account and the other a business checking account. The check-kiter is taking advantage of the "float" or number of days between deposit of checks and collection of funds. This may be used to conceal cash shortages at the end of a period by depositing a kited check into your account which would bring the balance into agreement with the books. A CPA should request 'cut-off' bank statements to detect frauds of this type. 

• Inventory shortages
• Profit declines or increases in expenses
• Slow collections or payments 

Fundamental controls that should be in place:

• Separation of duties; employees concerned with receiving checks and cash should not also be responsible for entries into the accounts receivable records. No one person should handle a transaction from beginning to end and if this is commonplace in your place of employment you're asking for trouble.
• Management should be provided with accounting department operating statements monthly.
• Always check the background of prospective employees and know these employees to the extent that you may be able to detect signs of financial or other personal problems; a major red flag when funds start disappearing.
• Only those with proper authorization should be placed on payroll duties.
• Make sure that an employee who's in the position to mishandle funds is adequately bonded. If those who would commit this crime understand that a bonding company also has an interest in their actions they may think twice about their plan to embezzle.
• Spot check accounting records and personally approve unusual payments etc. There is usually a very good reason why a financial request doesn't 'seem right'.
• Never delegate the signing of checks or approval of cash disbursements unless absolutely necessary and never sign blank checks or leave a supply of signed, blank checks when you're going to be out of the office.

• Internal controls - probably the most effective safeguard
• Independent audits - not only do these audits discourage fraud but will most likely uncover any improprieties once they've taken place
• Fidelity coverage - will help recover what was lost