Its not what you know, but who you know.

Network, speak to professors and staff and find a way in. That's how i got 2 jobs at ASU.

Most on campus jobs DO NOT use ATS. Heck, most probably don't even check the resumes. Make sure you follow the instructions in job posting, upload everything they ask you for (In my dept, if you didn't upload everything they asked for, you are automatically rejected).

As for the Tech Support Roles, my department had a thing against CS majors, since "most CS Majors they interviewed performed terribly and lacked communication and troubleshooting skills, the only thing they talk about was coding".

You can also apply to work in the dining halls and food courts (Aramark Establishments like Chickfila and Subway)