The application process is long, frustrating, and expensive. It can be extremely stressful. Approach it with confidence (but not cockiness). Be aware of your strengths and your weaknesses. Know that you may not be accepted (even if you have excellent grades and test scores), and prepare yourself mentally for this possibility, especially if your GPA and test scores are below the national averages. Come up with a backup plan. What will you do if you are not accepted by next summer? Reapply? Go to graduate school? Consider a different health profession, or another profession altogether?
You should begin answering these questions now. You may not want to think about this reality, but if you do find yourself in this situation, you will be glad you have some some preparation. Also, do not get discouraged as you hear of your friends getting interviews and even acceptances before you. Many people are accepted late in the process. Congratulate your friends and share in their happiness.
Strategies for improvement
If you are not accepted, take some time to evaluate your application and identify areas that need improvement. If your standardized test scores are lower than national averages, reconsider how to best prepare for these and take them again. If your clinical experience is light, find a way to gain more. If your GPA is lower than you'd like, consider enrolling in a post-baccalaureate program or a graduate program (Public Health? Epidemiology? Genetic Counseling? Health Administration?) to demonstrate that you can succeed in advanced science courses. You might even find that these careers are a better match for your interests and passions!
GAp and bridge years
Tens of thousands of students apply to healthcare graduate/professional schools each year, and the application process is extremely competitive. It is hard to 'stand out', as most of these applicants are like you - they have done well in college, have a strong passion for healthcare, and have lots of clinical experience. One way to set yourself apart is to take some time to experience 'real life' before applying. Find a job in a new city! Volunteer overseas, in the US, in communities with need! Teach in America or abroad! Gain life experience and stories to share!