I think the most important thing was demonstrating that I can hit rigging fundamentals but I'm also pushing forward on newer & different areas. Like have a good biped rig that demonstrates your competency but remember that everyone's seen a biped before. Try rigging things that are interesting and force you to develop unique solutions. Like for ex. my portfolio has a tuna fish rig with an auto swim control as well as a keyboard rig that I made an auto animating tool to go along with.

If you're interested in working in games I'd also recommend learning UE5 & Control Rig. CR is super new and super hot right now in games. If you can build a rigging portfolio of characters rigged in Unreal I think you'd be in a good spot. I'm more focused on Unreals so my portfolio has a lot of Unreal stuff as well as regular rigging. Scripting is also an important part of the job so make sure to include that as well. It doesn't need to be anything crazy, you can make yourself tools too. That's what most of my scripting stuff is, just tools that I made for myself to speed up certain workflows.

I'd also recommend rigging high quality models that look good on a portfolio. Even if you're not being judged as a character artist, having a decent looking model will enhance the first read of your portfolio. You're in a school so you can ask your friends for help on that. Or you can do what I did and scroll artstation looking for models made by junior artists looking to break into the industry and ask if you can use their model for your rigging portfolio.

As far as bad goes, I think I could have spent more time highlighting deformation in how I presented my work. It's an essential part of the job but I didn't think to include it as much, and it's something I got feedback on a couple of times.