Check out this informational site about shadowing!
Some tips for shadowing include:
Act and dress professionally. Shadowing involves a health care professional providing you with an opportunity, but s/he must have confidence to allow you into his or her practice. [For more on professionalism, see here.]
Follow any particular protocols set forth by the medical / health institution. Approach this as though you were applying and interviewing for a job. Be prepared to be turned down; some institutions are inundated with requests for shadowing, and the providers do not always have time to accommodate the number of requests coming their way.
A shadowing opportunity may be easier to find in your hometown or home region, using family or community contacts, but still be sure to follow the procedures set forth by the particular institution. If, however, you do not have very many contacts within health care, you could begin by volunteering in a health care setting and meeting health care providers that way. Note that volunteering is not the same as shadowing, and you would still need to follow the particular institutional protocols for obtaining access to a professional through shadowing.
Always have a resume ready and be able to articulate to the provider what your objectives are for your shadowing experience. Why are you interested in this profession?
Be prepared! Take a notebook with you where you can take notes. Ask engaged questions of the provider, but only at the appropriate time.
Always talk to a pre-health advisor if you have any questions or are experiencing challenges in gaining shadowing experience.
