Some universally important skills that I wish I had been a lot better at in college:

• Networking and selling yourself. None of the other (professional) skills you develop will matter if you can't get a job where you use them.
• How to collaborate effectively.
• Setting priorities and time management.

Beyond that, it's very important to know what your goals/values are. What do you want to get out of an ideal career? Why are you majoring in physics? It's hard to optimize before you know what you're optimizing for.

When I was at college, I didn't just pick up universally useful skills, but also skills that would be a lot more costly to learn once I graduated. So, for me, that included:

• Glassblowing
• Machine shop
• Wood shop
• Costuming
• Musical Theatre lyric writing
• Ballroom dance
• Swing dance

It would be a lot more expensive to pay for some of these lessons now, to schlep to a studio, and/or to get the kind of structured instruction I got at school. So I got to pick up some useful, unusual skills and have gotten more of my programming from Udacity.

I don't use all of these skills that often, but you might value a skill for the different frames of reference it gives you as much as the actual applications of the skill. I like that now whenever I pick up a piece of glassware, I automatically think about how it was made and get a little jolt of joy.

Getting along with people that you did not initiate associate with, and who you wouldn't normally initiate association with.

I chose my classes, but I didn't choose other students who also chose those classes. Some of them had never met an atheist before, and I hadn't spent time around proselytizing Christians in quite a while. Learning how to get along was highly unexpected and highly valuable.

Things you should aim to learn in classes:

-You should take enough math so that you can take set theory and formal logic and understand both of them

-You should take enough analysis (or calculus) so that you can think intuitively about continuity and about limits. You should also be able to think about when it makes sense to be thinking about the slope of a curve or the area under a curve. (this bullet probably goes without saying for a physics major, but is included for readers other than the OP)

-You should take enough English (or other writing intensive classes) to be a solid writer

-You should learn at least 2 programing languages (you probably only need to learn one in class, the second will be manageable on your own once you have learned the first)

-You should learn enough literary theory that you can casually and intuitively identify the social and artistic practices involved in the creation and maintenance of false categories and similarly identify the social and artistic practices involved in creating and maintaining a sense of “naturalness” about practices which could and should be legitimately questioned

-You should take game theory (imagine a big star drawing attention to this one)

-You should take macroeconomics with calculus and microeconomics with calculus. Some schools offer intro versions without calculus. For optimal time allocation talk to whomever you need to talk to (Professor, advisor, Dean, department chair, etc) in order to skip these and go directly to the versions with calculus

-If a history professor has a good reputation for teaching, take at least one class about a time very different than your own. Realistically, any group of people more than 200 years back should seem crazy to you. A good red flag to identify poor history teachers quickly is if they ever use the word “we” to describe a group that includes themselves and people who died before they were born.

-If your school has a good film class (ask students), take it. This isn’t so much practically useful, but if you substantially improve your eye for film you will be able to get a lot more enjoyment out of film for the remainder of your life.

You can't go wrong with writing, as it is nearly universally required and will be among the last skills to be Turing'd. A STEM major who can write well is a scarce commodity, if the GRE scores are any indication. (I would not recommend taking a course to improve your writing however. Just start writing a blog or something. And read Eats, Shoots & Leaves.)

If you have trouble socializing, learn how to do that. Most jobs opportunities come through socializing. Even the jobs that are advertised still require a competent interview.

For most people, college is the last chance you have to interact with smart, ambitious people in fields outside your own. You should take advantage of that diversity while you can, as it will pay off both in rewarding friendships and intellectual stimulation down the line.

Fellow physics undergrad here, hoooowwwwyadoin? I'll write of some stuff I've learned is important, and I'm quite interested in other LessWronger's opinions.

I think one important thing to learn is how to understand something, and how to notice when you don't understand something. I can't tell you how many students sit at the front of the room, nod happily along with the teacher, memorize all the equations, and still have no idea what any of it MEANS. Not only that, but they don't even know that they don't know what it means. What has worked for me is to get at least 2 textbooks on every subject I study and learn with those and the teacher. Each book hits problems in a different way and has different visuals and such. Gaaah sorry that was off of your question kindof.

Learn programming on your own. It's easy and most intro to programming courses go waaaayyyy too slowly.

Statistics is very important and most intro classes won't be enough. You can learn the statistics as you do research and need it, or take advanced classes that still won't cover enough ground.

Learn how to write. Note: most English 101 style classes don't actually teach you anything. Take a more advanced essay class or two.