Communication skills is most valuable aside from the technical skills. The ability to write bug reports, describe software errors, empathise with coworkers, and reason critically are essential to the job.
Technical skills are also important - such as programming, systems analysis, usability - are good to have. But this also depends on what you want to do as a tester. If you just want to test software similar to how a customer uses it, then you don't need to know programming. Analytical skills though play an important part. However, if you want to test the actual code used to make the software, then programming skills are required.
I now work for a gaming company and if you choose to follow the route of testing code or being a developer, then learning Java (Android) and Objective C or Swift (iOS) should be on your plate of courses. I would recommend learning how to test smartphones and tablets - it's a fast growing area and there are not many people who can do this.