I was able to determine which part of the pharmaceutical industry I wanted to enter. During my time at Mayne Pharma I was exposed to many different aspects of the company's operations and this allowed me to pick an area of interest
What I wish was different
I wish that I would have been able to work more directly with the sales team once I decided that this was an area of interest. Unfortunately, their policy dictated that interns could not get involved directly with sales.
Advice
Do not limit yourself to one aspect of an industry. Try a very generic and wide scoped internship in a field of interest. Then determine from that experience what area you'd like to specialize in.