What standard PCB notes should I use?
Identification:  


client's name,  
(project ID),  
unique PCB ID


PCB metrics:  


material,  
CTI (Comparative Tracking Index),
thickness,  
color,  
number of layers,  
layer stacking: reference to Gerber filename for each layer,
copper thickness,  
solder mask color,  
silkscreen color  


Panelization  


Tooling for PCB edges: V-cut or milling,  
PCB outline drawing with tolerances. This may be as simple as a rectangle, but this board's outline consists of 52 line segments 


Layout  


If there's room for it some shops like to add a quality logo (like UL) and/or a production date to the silkscreen. Tell them which area of the PCB they can use for this.