Habits I wish I started in my 20s as a 30 Year old

Here's what I'd do in no particular order but the most important ones are up top.

1. Saying No - Making 'no' a default as opposed to 'yes', this more so in later 20s. Its controversial because people say 'your 20s is about saying yes to everything' and I did that quite a bit, but its probably better to say "your 20s is about saying yes to some things and no to everything else" because yes opens up life but no defines it. Anything I'd have to actually think about I'd say no to, probably didn't want to do it bad enough anyway.
   

2. Quitting - Quit fast. Unsatisfactory jobs, Unsatisfactory relationships. This is a muscle. I still struggle with this because my whole identity is pretty much built around "I go at things until I get what I want", but even now, with this frame of mind, I struggle to do it. It's just my brain wiring, but if it isn't your brain wiring, and you are able to quit something that's highly unsatisfactory but don't do it because of societal / familial expectations, I'd just quit so you can create space to actually do the things you want.
   

3. Proactive Communication - This is probably the best skill you can learn to navigate society. Understand your emotions, intentions, wants, desires, learn to articulate it and make proactively communicating what you want a habit. The people that are bad at this, live reactionary lives. It's quite sad, I developed this much later in my 20s, about 28 but it literally boosted every aspect of my life since I started it. It allows me to build the relationships I WANT. Build meaning, people treat you the way you allow yourself to be treated, in business, romance, friendships. Get things clear and people can help you grow and be a support line for you rather than objects in space you react to.
   

4. Keeping a Schedule - Building a schedule is basically the same as drawing a map for your life on a micro scale.
   

5. Journaling - As a HABIT, this actually teaches you about yourself and your emotions and clarifies your thinking A LOT. It overall makes you a much better communicator overall, your ideas, likes, dislikes and desires. I picked this one up in maybe my mid 20s , still do it at least once a week, keeps me sane and most importantly HELPS ME MEET MY DEEP NEEDS FOR MYSELF so anxiety doesn't destroy my relationships or make me make stupid decisions.
   

6. Maintaining financial awareness - I learned about financial rules and principles around 29, which kind of sucks, but I've gone so deep into it, I have peace now. I look at my friends that are still trapped in the mindset of 'things will work itself out', despite hitting their 30s, and even for those that have 'enough' they're not actively trying to learn or get better at financial literacy. Its a sad truth that the phrase 'suffocating with money problems' is commonplace by the time you're 30 - 40. A lot of it is just building a fund for emergencies, paying off debt, and living on less than you make, but I'd try to read and get deeper each year as a habit.
   

7. Defaulting to Experts - Easily explained, but the converse is actually the issue. Listening to people that AREN'T doing the thing you want to do does more harm that not listening to them in most cases. Its a step back. I'd just ask for proof of concept from anyone giving advice if it isn't blatantly obvious they've already accomplished what I'm looking for, anyone else I'd politely nod and see if anything they said fits into some way I can challenge the confirmed information I already have.
   

8. Leaving before the party ends - In every way, the bar, the club, the relationship, the job, the date, the conversation. I'd just make a habit to leave not necessarily on a high, but just the moment I'm bored and trying to create something out of nothing. Especially with conversations and dating. If the person isn't making an effort, despite however attractive they are, or however successful they are, boring personality or not, its now unacceptable to me to carry an entire conversation with a WHOLE ADULT that's giving NOTHING back.
   

9. Quality Sleep - The energy I have in my 30s after quality sleep is phenomenal, now I dream about what it would've been like if i actually tried to optimize my sleep in my 20s lmao.
   

10. Skin Care - After 30 and kids come into the equation, you start to see the real effects of lifestyle over 10 years on people. I didn't put exercise on the list because I've maintained that habit since teenage years until now, and I always ate pretty healthy, but I didn't intentionally care for my skin, which was fantastic until about 1 year ago. It no longer can handle popping zits without leaving scars, where as before it was easy to just pop and it'd heal smoothly. Now I invest a significant amount into my skincare because looking good is a huge part of feeling good for myself personally.

Good luck!