Advice about what to focus on while preparing for undergrad full-time interviews

So to make a long story short, I am not one of the people who spent a bunch of time preparing to work in IB. I'm a senior who majored in finance and is in his final semester of undergrad, and I guess I'm just looking for what I should emphasis in an interview that relates to my appeal as a candidate.....interviewing is not my strong suit. I am likeable, but I just feel like interview questions are very vague and I struggle with how to answer them. "why do you want to work in IB, why this bank" etc. (not making excuses, just struggle with this part of interviewing)

I studied hard and have a good understanding of finance/business (for a college student at least). I am qualified but standing out in a sea of "top tier candidates" who look better on paper has been challenging. 

Any advice on how you presented yourself during an interview for IB Analyst, Sales and Trading, or Equity Research would be very helpful. Even short surface level generalizations. 

Also, is there anything you would recommend studying that relates to Excel/Financial modeling? Thanks