Reddit, how do I start my own computer repair business?

A little background: I regularly fix up broken, virus infested computers for people in my area. I charge a small, routine flat fee of $50 for the full repair. I have been doing this for roughly half a year and maintain roughly a $1500/month income from this.

My question goes out to an Redditor with experience in this area. What do I need to do in order to start my own business? I am very experienced, but have no degrees/certifications.