Invest in yourself.
You are your greatest asset. You have an incredibly high earning potential and you can typically earn money for 40 years or more (increasingly earning more as you gain more skill and experience).
Take care of yourself in the same way as your best investment: maximize its potential.
Invest in gaining knowledge, skill, and experience. I am not talking about going to college or getting an MBA but in things that push you to learn something new in areas you care about.
Invest in your longevity. The healthier you are, the longer and better you can work. Eat right and get plenty of sleep. Stay away from vices that dramatically shorten your lifespan like drugs and alcohol.
Invest in your ability to work with other people. You will be amazed at what you can accomplish with a team by your side. You also can’t get very far on your own.
Invest in good habits. Serve others and give generously of your time and money. As your wealth increases, your habits are just amplified.
Invest to become the best version of you that you can be.
When your best investment is staring back at you in the mirror, why would you look anywhere else?