Gauff won her first Grand Slam title at the US Open last year under Brad Gilbert but split with the noted coach this month after her title defence ended in a frustrating defeat by Emma Navarro in the fourth round where she produced 19 double faults.
"There are other parts of my game that I want to work on too, but the focus right now is the serve," Gauff told the WTA Insider in Beijing after confirming the addition to her staff.
"When I serve well, I play pretty well. For me, that's the basis for my game ... Already, the little bit we've done has made a drastic improvement to where I was three weeks ago.
"At this point, there's not a crazy amount, like going through a technique change or resetting everything. It's just subtle things that, doing it for a week now, will help me."
Gauff said she was excited to work with the 45-year-old Daly, who previously coached Denis Shapovalov.
"I think this is probably what it will look like next year too. I'm super excited for a new change and hopefully to improve other parts of my game," Gauff said.
"Working with Brad was really great and obviously we had a great partnership. It was just time to do a reset, a refresh and add some things in my game that I felt like I need to do to have a better season next year."
Gauff will meet Frenchwoman Clara Burel in her opening match in the Chinese capital this week.