Freelancing is likely to be a great option for you.

I run Expert360, an online marketplace for freelance professionals. We focus on bringing businesses and freelancers together to get work done, often within days or even hours. The site gives you the freedom to bid for contract work that interests you and suits your professional skills. Kind of like a matchmaking service, but less romantic. Freelancing will give you the flexibility to work on growing your business, while also developing your professional skills and giving you a stable income, no matter where you’re based.

Ironically, I used it in the start to supplement my own income whilst I was trying to build a business. :)