Every month

Enter every sales invoice and supplier bill for the month, and approve the drafts.
Record every receipt and payment. Import the bank statements.
Reconcile every bank, cash and card account to the statement's closing balance.
Check the Receivables Aging Report and chase what is late; check the Payables Aging Report and pay what is due.
Post depreciation for the month (or check the automatic run did).
Run the pay run: approve, post, generate the WPS file — and Record salary payment once the money has left the bank.
Check the trial balance balances and look at anything on an unusual side.
Read the profit and loss and balance sheet for the month.
Close the month on Periods, and set the lock date once it is reported.

Every VAT period

After the last month of the period is reconciled, Preview the VAT Return and check each box against the entries behind it.
Compute and save, submit on the FTA portal, then File this return with the acknowledgement reference.
Post the liability, and record the payment to the FTA when it leaves the bank.

Open the next financial year on Periods before the current one ends — see Periods and the lock date.
Review every fixed asset's useful life and residual value, as the accounting standard requires, and correct any that have changed.
Review customers who will not pay and discuss a doubtful-debt provision with your accountant.
Give your accountant the trial balance, the fixed asset Schedule, and the receivables and payables aging reports.
Once the accounts are agreed, set the lock date to the year end.