To do what one is interested in or skilled at, rather than simply doing what everyone else does. You don't have to go to med school just because your sister did—you need to do your own thing.Andrea is very independent and usually just does her own thing.
do one’s (own) thing
tv. to do what one wants; to do what pleases oneself no matter what others think. I’ve always done my thing, and I don’t see a great amount of benefit from it.