Life insurance rates are based in part on longevity, how long you are expected to live.
So, the younger you are when you buy your life insurance policy, the lower the rate.
Other factors that will affect your rate include your health, family health history, occupation, hobbies, lifestyle, if you smoke or not, driving record, credit history, height-to-weight ratio, etc.
For instance, if you are overweight, you would pay a higher rate than someone who of a healthy weight for his/her height.
Other factors that may increase your rate would include DUI's, high cholesterol, diabetes, heart problems, chronic illnesses, smoking, depression, etc.
One way to help lower your rate is to compare pricing on your life insurance among several highly-rated insurance companies to help you find the most affordable premium.