When I was younger I enjoyed reading about finance and investing. The investment strategy I settled on was the three fund portfolio from:

https://www.bogleheads.org/wiki/Three-fund_portfolio

and I haven't seen any reason to change this in ~10 years.

I'd recommend poking around that site to learn about the philosophy of index investing. (You might still want to actively invest after reading that, but you should probably first understand some of the reasons not to.)