Never Make Late Payments
Late payments can make the most significant negative impact on your FICO credit scores. Late payments that have been made recently and frequently will hurt your credit score more then one isolated instance of making a late payment a year ago.
A late payment is defined as any bill that is reported by a lender to any of three national credit reporting agencies that is late 31 days overdue or more from the due date.
If for some reason you find yourself cash-poor in any give month do whatever possible not be late on any accounts that have already been reported as delinquent to a credit bureau. Of course to find out which lenders have reported you must first acquire your credit reports from Experian, Equifax and Transamerica.