The phrase 'successful practice' is correct and usable in written English.
You would use it to describe a successful experience. For example, "The student had a successful practice run before his test."
Dad had a successful practice here.
Interesting theories do not always translate into successful practice.
Gus, meanwhile, settled into a successful practice as a litigator in Detroit.
Dr. Hunter, a clinical psychologist, had a successful practice in Brooklyn Heights.
Hopkinson set up a successful practice as an electrical-engineering consultant in 1878.
Upon returning to New York, Brian enjoyed 14 years of successful practice with Cahill Gordon.
For years, Shore had a successful practice representing patent holders, mostly universities, whose intellectual property had been infringed upon.
In 1988, he and another lawyer started a new firm that was expected to be a grandly successful practice.
For twenty-three years, he had a successful practice as an orthopedic surgeon, with particular expertise in pediatric orthopedics.
Returning to New York, Halsted quickly built a successful practice that demanded his services at six hospitals.
He immediately moved from Virginia to Ohio because of his antislavery views and set up a successful practice at Coshocton.
