Basic recommendations:
• Create more order in your life. Live by a routine and set goals.
• Exercise at least 3 days per week. Lifting/sports/cardio are all great.
• Use a calendar and stick to it as closely as possible.
• Learn to focus + meditate
• Eliminate any unproductive or time-wasting habits (watching YouTube, browsing social media, etc...)
• Simplify your life. Work, hobby, socialize, eat, exercise, and sleep should be 90% of your day.
• Get a hobby that isn't exercise or work. For example, if your hobby is video games, expand on that. Create content (guides, videos, etc.) for your favorite game or contribute your skills to an indie game project. If you read, then you should write or review written works, etc...