Earn a bachelor's degree from an accredited college. You should major in a subject related to the field you're planning to study further. This will give you experience in a specific field that you can describe in your purpose statement during the PhD application process.
Take the GRE and try to achieve a high score. You should set aside a four-month period to study when preparing for the exam. You can purchase specific study materials such as GRE preparation books. You can also attend classes designed to help you score higher on the exam. Register to take the GRE on the Education Testing Service website (see References).
Research the universities you want to attend and find out what their acceptance requirements are as well as their deadlines for submitting an application. You should take into consideration the professors whom you'll be studying under and their past achievements. Also consider course subject material and the university's doctorate program ranking. Find this information by visiting the individual university websites and the Princeton Review website (see References).
Decide which universities you're best suited for and submit an application. You should include written recommendations from your past professors as well as a statement that details your field of study, your level of experience in that field and your future plans upon receiving your PhD (see References).