Perhaps the following posts on Stack Exchange may help:

What should a CS grad know? http://programmers.stackexchange.com/questions/16325/what-sh...

Advice for nontraditional CS student? http://programmers.stackexchange.com/questions/39243/advice-...

Personally, I believe the most important language-agnostic skill for any CS/engineering graduate student is the ability to model problems and solutions with pen and paper before diving into the code. The theory lays the blueprint for the house. The code is the bricks.