Two words:
Linear Algebra. Eat that stuff up when you get the chance. My University was too blind to offer the courses for my Computer Information Systems degree.
For proof: Right now with the Xbox 360 game we're working on, I use linear algebra every single day. I can't escape it. Dot products, cross products, etc. etc. In the past I have had interviews with EA, Ubisoft, and Relic. Two things that are common with them all: They ALL ask technical C++ and linear algebra questions.
For example they might say: How do you detect if two spheres are colliding? You can't say "Well I just use the collide commands in DBP". They will most likely laugh at you behind your back
One other piece of advice is to study up on your computer science theory, like design patters (singletons, etc.). If your University doesn't offer this, then get the books and study.
I'm kicking myself in the butt right now because I didn't study linear algebra formally, and I'm paying through the nose as I bombed several interviews due to lack of knowledge about simple linear algebra.