Went to a job fair to hand in my resume and applied online. I think they want to see that you take the time to do both as well as be confident for the first impression. First, there was a phone interview which was basic questions like why did you choose engineering, why this university, describe a time when you had a conflict working with someone and a brainteaser. Everyone had a different brainteaser. I didn't get it right away... they just want to see that you follow through in your solution. Second, there was a group interview. We got in groups to figure out this logic problem and then had to build something to support an egg while it was dropped from the top of a building. We had to prepare a presentation in groups beforehand. They asked mostly safety questions after the presentation. I would suggest keeping everything simple. I would also suggest to ask questions since most of the interview was describing the segments and listening to presentations... they want to see that you're interested and engaged. They also watch you watching everything so act attentive and don't be on your cell phone. Take notes etc. Everything was simple just don't forget that even though its relaxed you are on an interview.

3 Mins Interview to "Vibe Check" and test your english, then HR Interview, then User Interview. In my opinion, it's better to be as natural as possible, but prepare your technical knowledge and professional attitude.