If your job is a long-term investment, with the promise of future earnings, you would not be willing to switch professions. The only way now is just a side job.
There are a few ideas about the side job that may be right for you.
1. A freelance writer
Perhaps you are a reliable author. Why you not try to write a book? Try to express some of your ideas. Perhaps you have had some success. Tell it in the book that you wrote. You can sell it as an ebook or print book.
Maybe you have a good camera. Use it! Selling on the site or in a newspaper company.
3. Open a catering business
Are you a good cook? Make a cake that was vogue. Advertise on your website or blog, or try to use facebook or twitter to promote it.
4. Creating a website or blog and use google adsense or the like to make money.
5. Swiftlet breeders