Besides the daily operation, there are some finance tasks that recur. Once you know them, they will not catch you off guard.
VAT reporting — calculate and report VAT for the period.
Bank reconciliation — reconcile your bank postings against the accounts, so everything balances.
Reminders — follow up on unpaid invoices.
Year-end — close the financial year correctly.
Ongoing reconciliation and follow-up mean the figures can always be trusted — and make year-end in particular far easier. The more you do on an ongoing basis, the smaller the pile at the end.
Read more in VAT reporting, Bank reconciliation, Reminders and Year-end.