You don't want to come off as the entitled rich kid. Whether you bring the bag into the interview or leave it in a closet, make sure the bag is conservative and simple (no logos, no designer bags that don't bear a logo but are easy to spot, such as Bottega). Find a random black leather bag that screams "practical and polished." You want to be confident, but also humble (particularly if you're interviewing for an entry level position, future underling), plus ambitious, hard-working, collected and well-spoken.
No MD who pulls 80 hour work weeks to support her bag habit wants to see you waltz in with the same large Fendi peekaboo she treated herself to last year after bonuses were paid. Even if you bought the bag yourself by saving every penny you could from your part-time college job. What are you going to say when you're asked about your work experience? "I decided to work during college because I really really wanted a designer handbag." Wrong answer.
Keep jewelry to a minimum, think the opposite of a model in a J Crew catalogue loaded with baubles and bangles. Pearl earrings and a necklace are appropriate. Your jewelry shouldn't make noise when you move. A watch shows that you're responsible and timely, but once again, be careful, no cartier or rolex, etc. If you're interviewing with a male, a designer bag could fly right over his head but he'll spot a flashy watch in a second.
No flashy shoes. Black leather pumps. Ivanka ***** Indico pumps are a good choice.
Simple, well-made suit as well. Pinstripes and patterns are tricky, when in doubt, solid navy or black is a no brainer. Simple blouse as well. No boobs. You don't have to dress like a nun but you need to look composed. Make sure everything fits perfectly (pants are the right length with your heels, blouse doesn't pull, etc).
Have many copies of resume in a portfolio. They should be printed on a nice quality paper (just look for resume paper in staples). Ruthlessly edit until you are 100% sure there is not a single typo (although of you have the interview set up, HR has already looked at your resume).
If you have a tendency to play with your hair when you're talking, pull it back. You're not doing yourself any favors if you're flipping/twirling while answering questions.