To secure a low rate, focus on three factors: credit score, debt-to-income ratio, and down payment. Your score should be at least 620 to get a conventional loan with most lenders, although some require higher. But the higher your score, the better rate you should get. To improve your credit score, focus on making payments on time, paying down debts, and letting your credit age if you aren't in a rush to buy. Your debt-to-income ratio is the amount you pay toward debts each month, divided by your gross monthly income. Lenders typically want to see a debt-to-income ratio of 36% or less. To get a lower ratio, you either need to pay down debts or earn more. You don't necessarily need a 20% down payment to get a good rate, but the more you save, the better your rate will likely be. If you don't have much for a down payment right now, it could be worth saving for a few more months.