Summarize:

Although the focus of your undergraduate degree is not vital, you should choose a field that is relevant to economics to begin your education. Focusing on economics right away will help prepare your for advanced schooling and your eventual career. Complete your undergraduate with a high GPA, shooting for the best grades you are capable of. Focus on economic courses, but try to get strong grades in all of your core classes as well. Study for the GRE and receive at least a 800 in the mathematics portion of the test. Prepare for the GRE well beforehand and take the exam as seriously as an application. You can retake the exam if your scores aren't satisfactory. Choose a school that best suits your needs and apply to the school as early as possible. Apply for any scholarships that are available, and then enroll and complete your master's degree in two years. Take note of the subfields you enjoy the most - microeconomics? Macroeconomics? When you apply for a Ph.D, it'll be important to choose a specialization you want to know more about. Although pursuing a master's degree is not essential to your doctorate program career, taking two years and spending the money could be worth it in the long run. Do this throughout your undergraduate and master's degree programs, and curate the relationships with as much attention as possible. Learn from these professors and illustrate your continual commitment to the field of economics. Ask them questions as often as possible and spend time with them during their office hours. By studying hard and communicating well with professors, you will be able to build relationships that will not only help your studies and focus, but also help with letters of recommendation later on.
Receive an undergraduate degree. Take the Graduate Records Exam (GRE). Complete a master's degree in economics. Develop meaningful, professional relationships with at least two professors.