I have a great idea.
First, you need to become a black belt in karate or any other form of martial arts. Then you need someone to spar with. If you don’t know, sparring is basically practice fighting. You can get a buddy to spar with or open up your own dojo and spar with your students. Your choice. Next, you need to spar out in the sun and not wear too much sunblock. Don’t get too burned out there. A couple hours should do. After you are done sparring, you should have yourself a nice spar tan. Repeat 299 times.