One major decision I recently made is to try to minimize the time I spend consuming internet- and video-game-based entertainment. I realized that I consider almost all of the time I spend on those things to be effectively completely wasted. It doesn't make me happier, it doesn't get any of my schoolwork done, it doesn't each me anything, and it doesn't facilitate any social interaction (unless it's a video-game played at a LAN party or something, which I'd consider differently). I have observed that both I and most of my friends waste almost all of our free time on such things, and we could spend that free time either being productive or doing something that is slightly higher-effort but much more rewarding (like reading books, playing piano, playing a board game or talking with friends, going for a hike or otherwise exploring the outdoors, etc).
I've spent the last couple years trying to spend more of my time on those worthwhile things: trying to prioritize my classes, piano, outdoors, exercise, reading, etc. But I've finally realized that the core problem is my (and pretty much all of my peers') obsession with/addiction to low-effort activities and low-effort entertainment. I just need to judiciously avoid stupid low-effort wastes of time, and I'll much more easily find other more productive things to do during that time instead. It's working out well so far.
I think my parents had a better college experience than any of my friends or I am currently having. They made better friends and did more memorable things with them. I blame the internet for stealing our time. If we didn't always have such easy access to stupid low-effort entertainment, we'd be motivated to find more worthwhile ways to entertain ourselves.
Generally speaking, low-effort things suck, the easiest thing to do at any given time is never actually worth doing, and the worth/productivity/happiness/reward gotten out of any activity is generally proportional to how difficult it was. Kind of like Reddit: it sucks now compared to five years ago because almost all of the content and discussion is much lower-effort now compared to five years ago.
I don't want to waste the bulk of my college years neither learning nor making/doing something cool nor going out and actually doing things with my friends. And the way I plan to start to do that is by avoiding the single foremost thief of my time: the stupid internet.
(Copypasta from a comment I just wrote; thought it might get more useful feedback and discussion here.)