What is the most effective way to capture additional attributes while creating an item in PD

Summary:

What is the most effective way to capture additional attributes while creating an item in PD?

Content (please ensure you mask any confidential information):

Root Item Class allows configuration of a single attribute group that enables capture of attributes e.g. Product Details attribute group with attributes like Material Type, Build etc. But there can additional attribute groups e.g. Manufacturer Part Details attribute group with attributes like Wattage Rating etc. Also some of these attributes may be required in PD but not for items that commercialized. We do have a separate class for items that created though PD but there are also item class that do not use PD.