I assume you're talking about a job interview. If so, one of the things you might work on is expressing yourself clearly in written communication. Are you talking about job interviews in general? If so, there are tons of books available with great information. I used Job Interviews for Dummies, which contains lists of all the standard questions employers ask. You'll be surprised how many use questions verbatim from the book.
If your job search is engineering / CAD specific, you can expect questions regarding:
* how much experience (years / hours / versions) you have in specific CAD packages
* your opinions of the strengths and weakness of certain CAD packages
* your strengths and weaknesses in using specific CAD packages
* do you know proper modelling and detailing practices.
Bottom line, they're trying to determine if you can make them money or not.
Some companies are using tests like Pro/Ficiency and giving applicants design problems, whereby they sit a candidate down at a computer and see if they really know how to use Pro E, or just put it on the resume.
I think you'll find a lot of general design questions in an interview. What you'll want to demonstrate is that you know proper part design practices. There are a lot of people who know how to drive the software, but don't know how to design an intelligent, robust model. I would also recommend learning how to design for manufacturing. Lots of people can design parts in Pro E, but then the part can't be manufactured. I would also recommend learning surface design; top down design practices; drafting standards (e.g., ANSI, ISO, GD&T); and analysis (you don't have to be an expert at Mechanica, but it behooves a designer to know how to perform their own basic structural and/or thermal analysis). You also would probably want to know something about configuration data management in a PDM or Intralink environment. Being able to demonstrate knowledge in additional packages like Behavioral Modelling and Mechanisms would be icing on the cake.
Specific questions, though, are going to depend on the position for which you're interviewing and the industry / sector of the company.