Start Early

The most important thing for a freelancer is to start as early as possible to maximise their potential. It's very simple really, much like the Founder's effect. If you're late to the party, you'd lose out on opportunities. Many successful and highly sought after freelancers started as early as their first year in college. With flexible and self-determined work hours, only one's initiative matters. You could start with Talent Hut, which has a big repository of online jobs, and also prioritises your career. Also keep posting your code on GitHub, CodePen, and other public code vaults just to be in the game. Working on self will not just improve your competence, but also will increase your chances to get noticed.