Is there a reference PCB design for hobbyist manufacturers?
I would say "Hello World" is more related to the usage of the EDA tool so that you can create boards according to tool's rules and processes which would validate properly in the tool and have correct Excellon and Gerber files as output. I use EAGLE, and it has several examples. As you have already chosen the tool, just search something like "KiCAD usage guide for newbies" over internet.

As to manufacturing standard, they are relatively simple, every manufacturer should have requirements listed on their websites. To name those coming to my mind:


number of layers
size of board, thickness of the board
copper thickness
minimal width of conductors
minimal distance from board edges, and from polygons to conductors
minimal distance between pads/vias; minimal diameter of drills
material of board


In general, start with defaults if you do not have really special requirements - e.g. high power, high EMI requirement, high-frequency etc.

Respected manufacturers always check and validate manufacturing files before production, and return back to you for corrections and suggestions if they may have issues during producing. In general it is their business and making board which will not make well will harm their reputation heavily.

Competition on the PCB manufacturing market is really high (you can find dozen of such firms in China), thus I doubt you will have problems if you will choose one using word of mouth or positive feedback on the internet.