One thing that we see from undergrads is a failure in the basics of team working, most of the time they are working solo and save everything in dropbox.
Working with version control, git & github is something we like to see, CI knowledge is good, also writing tests for your code, all these things help show you aren't going to need 2 months of teaching before we let you near the codebase.
On a basic level, learn to use either OSX or Linux, it can be difficult for some people to jump in from a long term Windows stretch, so showing extra skills like using the command line can be a big plus. It may seem strange, but setting up a computer is actually not a simple task for some people, it can take a few days, especially when having never used Ubuntu for example.
One last thing to also take into consideration is the wider industry, if you apply for a job with knowledge of current industry standards and conventions, you might find yourself with a few more job responses. Technologies we use are PHP, JavaScript, HTML, Ruby, JRuby, Python, Node, Vagrant, Packer, Docker, AWS, Git, Github, Jenkins, Travis-CI, SASS.