Self-taught bookkeepers use a variety of courses, seminars, books, and other online resources to learn about bookkeeping and accounting. You can also learn how to use accounting software, like QuickBooks, which can teach you about the basics of bookkeeping as well as the technology used by many businesses.

A bookkeeping side hustle offers incredible flexibility. It allows you to balance work with personal life. It also opens opportunities to work with a wide range of clients from different locations.

"A bookkeeper records the financial transactions of an organization and takes care of day-to-day functions such as recording sales and invoices, paying bills and processing payroll," Stephens said. "Accountants take the financial data and analyze it to help organizations make financial decisions."

Bookkeepers and accountants sometimes do the same work, but have a different skill set. In general, a bookkeeper's role is to record transactions and keep you financially organized, while accountants provide consultation, analysis, and are more qualified to advise on tax matters.