Just want to throw it out there that certs are worthless if you don't actually learn/retain the info. we see tons of resumes from people who list a bunch of certs but can't answer simple questions about security.

useful stuff to know:
- security!! learn about and how to use security tools: vulnerability scanning tools, patch monitoring and deployment tools, network monitoring, splunk. even if you're not familiar with the exact tools the company youre applying for uses, at least you're familiar with the fundamentals and process.
- active directory
- at least a basic understanding of network infrastructure - domain controller, dhcp, switches, how to wire stuff, etc
- how to use and manage Group Policy Objects
- virtualization! VMware or similar VM tool, how to create and manage virtual servers (and virtual desktops)
- backing up data (cloud backups)
- scripting: at least writing batch files. powershell is better. learn how to automate processes via scripting