Performance (Any Class)
Novice - The performer has overcome stage fright enough to perform in front of other people, usually small groups.
Apprentice - The person is now able to handle larger groups, and more intricate events and skills showcasing their talents. They may be less distracted by cheers or jeers in the arena, able to concentrate on their blacksmithing with less burns from an open forge, or hold their melody of song better while in a loud environment.
Journeyman - The performer can now better address their audience, looking them in the eye and singling out people for their attention while not ignoring the rest in the area; a great method of possibly gaining tips. They are ready for larger audiences and street venues.
Expert - Now they are able to lose themselves to their performance without risk of losing the audience. Their presence commands attention and each motion, each words seems to spike with their gained confidence and art. When they perform, eyes are definitely watching.
Master - The performer now has full concentration when working, and it can take a lot to distract them from such work. Not only can they work the audience with what they do, they can teach, lecture and explain things without missing a beat to their designated task. They are able to lead parades and bands, and are worthy enough of putting on displays of skill and form at the Imperial Palace.
This is a skill designed with entertainers in mind, though not the Entertainer class alone. This includes fighters putting on a show of bloodshed and jeering at the arena, priests in their temples preaching in glorious display, artisans sculpting in front of customers in the market bazaar and even blacksmiths beating their hammers to the open forge. Life is art, and the art and life of performance is in of itself a skill and talent.
Having another skill available for Entertainers is always a plus too and can allow them more pay for what they're best at.