Ask HN: Tips for students before starting their first job

Hi, I'm 19 and currently in my second CS semester. I've got some projects on my portfolio, did some internships and will start an job as an research assistant at an institute next semester. However, I really have no clue how I can prepare myself enough before landing my first job after university. The only things I can find are: build a portfolio and contribute to open-source.

Which advice did/would have helped you landing your first job after university? And whats your best tip for life in general?