To get a second mortgage, you must first determine if you qualify. Since this type of loan is risky for the lender, they will take precautionary measures to make sure you are able to pay what you borrow. Having a good credit score will give you better chances of approval. This will also provide a basis for the interest rate on the loan. The higher your credit score, the lower the interest rate so it is best to work on improving your score for a few months before applying for a second mortgage. Other documents the lender will require are proof of income, debts, and other financial information. Have these ready with the application form and you should have no problem getting the second mortgage loan.