\tTo prepare a trial balance we need the closing balances of all the ledger accounts and the cash book as well as the bank book. So firstly every ledger account must be balanced. Balancing is the difference between the sum of all the debit entries and the sum of all the credit entries.\tThen prepare a three column worksheet. One column for the account name and the corresponding columns for debit and credit balances.\tFill out the account name and the balance of such account in the appropriate debit or credit column\tThen we total both the debit column and the credit column. Ideally, in a balanced error-free Trial balance these totals should be the same\tOnce you compare the totals and the totals are same you close the trial balance. If there is a difference we try and find and rectify errors. Here are some cases that cause errors in the trial balance\tA mistake in transferring the balances to the trial balance\tError in balancing an account\tThe wrong amount posted in the ledger\tMade the entry in the wrong column, debit instead of credit or vice versa\tMistake made in the casting of the journal or subsidiary book