[cyorir]

I can do well enough on programming challenges at a place like HackerRank. However, I very rarely actually get to the technical interview in a job application; most commonly, I apply and don't hear back from the company. So as far as I'm concerned, I need better something but that something isn't better skills.

[oblio]

More networking, possibly better networking (easy, I think).

Better university name (hard to do).

Better company names (not that hard, I think).

(Major) Open Source contributions (not hard, but time consuming).

Other studies or certifications (easy).

If they're not calling you, I'd work on these.

[user5994461]

You forgot the most important. More real world experience, and a well formatted resume.

[cyorir]

Definitely all things I'd like to work on.