Missing (“defaulting on”) payments on loans and even on smaller bills like power and phone will reduce your credit rating. Things like shifting debt from one account to another (like from one credit card to another card), applying for too much credit or for too many payday loans, having debt collectors involved or going through an insolvency procedure like bankruptcy or the no asset procedure will also have a negative impact on your rating. Making a hardship application to your bank or other lender is also taken into account.