Want to teach.

There are many ways to earn by teaching while you are still a student. The first step is to let others know you are willing to teach for a fee. Announcing it here helps in spreading the word but will not guarantee of getting a paying client.

Option 1:
There are parents who are willing to pay for helping their child in learning and doing their assignments, especially in math. Establish a name that you are willing to do a tutorial and talk to parents with elementary and high school child in private schools and science highs.

Warning: Avoid clashing with professional tutors, they are doing serious business.

Option 2:
You can apply to any online tutorial site who accepts payments from the students. The requirements for tutor varies from site to site but mostly about you establishing a name as an active participant who gave relevant and quick answers.

My personal experience:
I used to do tutorials when I was in college, a relative of ours hired me for her daughter in high school, the subject was trigonometry. I was given a decent fee (equivalent to professional tutors in our area) I think because I'm her nephew and she made it her way in helping me financially for my studies. It ended when I can't do it already due to my school schedule.

Also back then, I voluntarily do the tutorial to my classmates and to lower-year students; that was for fun and for sharpening my knowledge about the subject. Free meals and snacks are a bonus plus favors for small things like bond paper, but most of all friendship.

Good luck to your hunting and I hope you find one that meets your expectations.