Segregation of Duties: the "rule of two"
Meaning that any task involving the finances of your small business should require at a minimum two people to complete.
Here’s a few examples
1. Bookkeeper records all receipts, Accountant reconciles all accounts to make sure what’s recorded in the books matches what happened in reality (as shown on the bank statements)
2. The secretary photocopies checks from clients, gives the photocopies to the bookkeeper to record, then the secretary completes the bank deposit with the actual check
3. The bookkeeper prints checks to pay vendors, and the owner signs and mails them