I was going to include a list of things that I've done/I'm doing, but I rather get fresh ideas and not bias the conversation.
If you're more senior, the biggest impacts will come from networking. Figure out where you want your career/life to go, then work towards that. Want to be CTO? Want to work at XYZ tech co? Want to start a business? Doesn't matter, make some friends and start networking.
I'm a big advocate for leveraging the energy of your youth, but make sure you're spending it wisely. There's more to life than working.
Remember it's ok to not code outside work, even if you want to advance professionally. An artisan don't work outside his shop.