Not sure I follow, can you expand the question. Are you refering to what properties should be added or are you referring to what attributes/code do you need to create properties?

https://world.episerver.com/documentation/developer-guides/CMS/Content/Properties/built-in-property-types/

@Scott Read

I am referring to designing page type with its properties. I am refering what properties should we create in page type not attributes. Ofcousrse, it depends upon the business itself. However when you see ProductPage in Alloy project, UniqueSellingPoints and RelatedContentArea are only the properties in it apart from prooperties from its base class StandardPage. It looks bit different than than the normal model class.