If you were in your mid-20's again and just graduated, what would you do differently this time?

I'm graduating from law school next year. Looking back at my life as a student, I feel like I've wasted so much money and time on things that I didn't need, didn't serve a purpose and/or didn't make me happy. I started taking an interest in minimalism, frugal living and zero waste over the past 2 years and I've made quite a bit of a change in my life. Actually been able to save quite a bit of money - though admittedly, I live in a country where education is very affordable, so I didn't have to take any loans or so.

Many things are about to change for me in the next year and with change often comes confusion and bad decisions. I've heard so many people regretting spending a lot or wasting their time once they were earning money for the first time, and I wonder what you guys would do differently if you had the chance to go back to that stage in life? I am probably looking at a very busy life where I'm building my career for the coming 5-10 years, but also a more than decent salary. Timewise, I might have to compromise for a while (though the long-term plan is to work a bit less, travel, and retire earlier than the legal age here of 67), but maybe there are still things that I should keep in mind? And how would you handle your first paychecks if you had to start over?

Looking forward to hear your responses!