Pro-Tip: Take the difference in balance and look for transactions in YNAB or your bank statement that match that value. If I'm off by $23.47, then there's usually a single $23.47 transaction somewhere that I missed. Makes scanning the bank statement that much easier.
Aquamarine Rhythm I do it totally differently. I go systematically down the bank's list matching+clearing in YNAB (or entering+clearing or editing+clearing). YNAB is typically sorted by outflow with previously reconciled transactions hidden to make matching very easy. Assuming it was previously reconciled, this process has never failed for me.