How to decorate extremely fine details
They = cake decorators

They have an artistic hand (I don't have one and cannot decorate anything).
They have lot and lot and lot of practice.
They have wasted a lot and lot of cakes and icing and fondant to achieve that level of perfection.

They have a lot of experience with making their own icing (and fondant) that will work well when decorating bags in their own controlled environment (temperature/humidity)

They usually use small pipettes (or syringes) and small pastry/decorating bags with fine points couplers.

As for "naming them", I assume you are talking about "cake decorators" and google will return gazillions entries.

Max.