Delinquencies are just one reason credit scores fall. Most people do not realize that balances on revolving credit has a huge impact on your scores as well. As a rule of thumb, you ideally want to keep your balances on credit cards, equity lines, etc. below 35%.The first thing you should do when trying to improve your credit score is to obtain a current credit report from all 3 credit bureaus (Equifax, TransUnion, and Experian). This will let you know exactly what is hurting your score the most, and give you a chance to identify anything that is being reported inaccurately. Dispute any errors immediately with each bureau to begin getting your credit back on track.
Many credit vendors offer "rapid rescore" type products, which tell you exactly what items to correct and what effect it will have on the credit score. Usually, you can fax the documentation needed and have the score raised within a few days. There is an extra charge for this type of rapid rescore.