1
general::
Phrase(s): have a good thing going
to have something of an ongoing nature arranged for one’s own benefit. • Sally paints pictures and sells them at art fairs. She has a good thing going, and she makes good money. • John inherited a fortune and doesn’t have to work for a living anymore. He’s got a good thing going.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Have matters arranged to one's benefit or profit. For example, Joe's got a good thing going with this new franchise. It Also may be put as make a good thing of, meaning "make something work to one's benefit," as in If we work hard we can make a good thing of this job. The first term dates from the second half of the 1900s, the second from the early 1800s. Also see HAVE GOING FOR ONE.
American Heritage Idioms