One thing at a time. Know the problem. Learn to listen. Learn to ask. Distinguish sense from nonsense. Accept change as inevitable. Say it simple. Be calme. How to work better, ten simple things that make a huge difference.
Your are your 'selfish' years. It's a decade to immerse yourself in every single thing possible. Be selfish with your time and all the aspects of you. Tinker with shit, travel, explore, love a lot, love a little and never touch the ground.