Working toward a PhD in the biomedical sciences provides training for your future as a research scientist. In addition to the research skills you will develop, the most important other skills that you must have to succeed as a scientist is being able to communicate your science with others, both orally and in writing. Your dissertation research will provide an opportunity to contribute new knowledge to your chosen field and to make exciting new discoveries that will be presented to other scientist in a variety of ways. It is important to note that success in biomedical research depends in part on peer review, which includes both informal peer review of poster and oral presentations, and more formal peer review of publications and grant proposals. It is important for you to look for opportunities (and volunteer) to present your research in small informal settings in your program. This will allow you to practice and gain confidence for presentations at the "big" meetings.
Posters and Oral Presentations
As a graduate student your first opportunity to formally present your research (beyond your lab/institution) will be at regional and/or national scientific meetings via poster and/or oral presentations. Attending such meetings is an important part of your professional development; you will see and hear presentations by other scientists, and network with new colleagues in your discipline. You will have many opportunities to practice your oral presentation skills in courses that emphasize discussion of the scientific literature, such as journal clubs, as well as at your research proposal defense, research seminars, and your final dissertation defense. Your mentor should provide feedback and constructive critique during the preparation and practice of your oral presentations. Be sure to seek opportunities to practice your talks often, e.g., at lab meetings, so you can get feedback from your mentor and other members of your lab. Some graduate programs offer additional courses and/or workshops designed to improve poster and oral presentation skills.
Publications
There are two types of scientific writing that you should work on during graduate school. The first is writing manuscripts for publication in scientific journals, and the second is writing research proposals. No matter what biomedical research career track you eventually pursue, whether academia, industry, or other, you must be able to effectively report your research findings clearly and concisely, including the background and rationale for your work, how you did your experiments and what the results were, and how you interpret your results in the context of a bigger picture in your discipline. You must also be able to write research proposals to justify new lines of investigation based on sound hypotheses and preliminary data. Many PhD programs require a written research proposal at an early stage of training, e.g. qualifying exam, and the culmination of your research endeavor will be a PhD dissertation that fully documents your original research contribution. Writing skills are usually developed by working closely with your mentor and other senior lab members and scientists. Some programs also provide courses and/or workshops designed to enhance scientific writing skills.