The most important technical skill would be proficiency with CAD. Apple uses NX, which is a very powerful CAD program that isn't usually available for students. Pretty much everyone in PD uses this on a daily basis, so you get a lot of experience in a short amount of time. Another skill you need is presentation skills, which can also be learned on the job. A presentation should have an overarching story connecting all the slides, so every slide is important. Apple is very detail-oriented environment, so graphic design plays a large role in constructing slides too.