This was my first major interview out of college, and it was a great experience. The interview took place at Normandy Farms, an outside location, and lasted about 45 minutes with two Operations Managers. One manager was from the Pneumovax/Pedvax IPT and another was from Varicella. Both managers were very nice and asked me specific questions regarding my resume, my future plans, how I work with others, and had a strong emphasis on questions regarding safety.
My best advice would be to go to the interview looking your best; appearance says a lot. Show them what you have to offer. This is an entry level position, so if you come with significant GMP experience, want to be involved in research, etc., then this is not the position for you. However, this position will open doors for future careers you can get with Merck.
Afterwards, you will have a short follow-up interview with a Merck recruiter who will ask you what days of the week and shift you want to work. You will not get a first shift position. Third shift if you want a life or have a family, second shift if you like to sleep in and get stuff done in the morning or late at night. In the end, you are not guaranteed the shift you prefer. In my offer letter, I was given a Saturday to Wednesday second shift position, but when I started, I was put on a Monday to Friday second shift position.
Don't lie. They will know because they've done their research on you. Be honest and respectful and ask questions! If you don't know what an SOP is or a batch record, ask for clarification. Be yourself!
Lastly, if you know somebody who can put in a good word for you that works at Merck, use them!!! HR gets thousands of applications for this job and you need to stand out!