The focus of your application to the College of Public Health should be on creating a body of evidence that you are ready for and capable of graduate-level work.

Your recommendations should, if possible, give specific examples of how you have demonstrated a capacity for graduate-level work in your experiences with the reference. It helps to have them from former faculty members, or people with whom you have worked or volunteered.

Your personal statement/letter of interest should specifically address your interest in public health, and your desire to attend this specific College of Public Health.  It should have a professional tone and be free of spelling and grammatical errors. What do you hope to accomplish with this degree?  What in your life to date has drawn you to public health?  Also in your personal statement, don't be shy about pointing out things in your application that you feel are strengths that exemplify your capacity for graduate work (this may be research experience, work experience at a level of significant responsibility, evidence of significant initiative or self-directed study.)

If there are blemishes on your transcript (for a graduate program, any grade of C or below should be considered a potential "blemish," and for the College this is especially true for math and science courses), you need to explain those grades and, if possible, show how you have improved your skills (in your personal statement or in letters of recommendation) in those areas (re-taking a class and receiving a better grade, doing some self-directed study that can be documented by a reference or some other means, etc.).

Successful applications to the College are rarely "perfect" ones -- rather, they are ones that highlight a candidate's strengths and experiences that are directly relevant to the skills needed in a public health graduate program (initiative, self-directedness, math/science skills, writing skills, community involvement, etc.) as well as ones that address any weaknesses and the steps the candidate has taken to remediate those weaknesses.