Ensure you have performed all tasks relating to the general ledger as described by the general ledger help reference topic: End Of Period Procedures
Confirm that your opening balances for the year have been entered or correctly transferred, including any final journal adjustments made by your external accountant or auditor for the prior financial year.
Review all your bank accounts and ensure all bank entries have been reconciled. All missing transactions should have been entered, and any duplicate entries removed.
Run a Cash Manager Transactions report for each of your bank accounts (Report Cashbook-0002) to ensure that the closing balance of each bank account agrees with your bank's statement(s). Or confirm these balances against your postings for the final period in your general ledger.
If they don't agree, check for missing or duplicated entries as per step 2 above and also confirm that your opening balance for the financial year agrees with your bank's statement, as the problem may be in an earlier year's entries, such as misdating of transactions before or after the prior financial year ends.
Ensure that all entries found in each of your bank accounts for the relevant reporting period have been reconciled.
Confirm your GST and other tax accounts agree with your GST and other tax reporting, as per what you have submitted to your tax authority.
Ensure that your wage accounts including any withheld income taxes, agree with your submissions for the year made to your tax authority.
Ensure that your superannuation or similar entries agree with your funds reporting.
Ensure that all unpaid supplier invoices and expenses have been entered into the system.
Ensure that a stocktake and/or stock report has been run and closing inventory values have been entered or adjusted as applicable.