Bookkeeping
Categorizing transactions and reconciling accounts through the month.
Bookkeeping is the steady work underneath everything else: recording what came in and went out, putting it in the right account and checking it against the bank. When it slips for a month, the cleanup takes far longer than the upkeep would have.
These guides cover categorizing transactions, reconciling accounts and keeping a chart of accounts that stays readable. Your accountant has the final word on how an unusual item is treated.