What is most efficent way to set up Product Attributes???

On a learning curve.....ok with setting up Products/Categories/Attributes/Images etc.
My question is...what is the most efficient way to set up product attributes?
Is the best way to:
a) set up the Attributes under Attribute Manager/Values
b) set up all the Categories/Products/Images

THEN retrospectively copy the required attribute to the product or Category??? This would seem more efficent than setting the attribute for each product as it is created...am I correct?

thanks

THEN retrospectively copy the required attribute to the product or Category??? This would seem more efficent than setting the attribute for each product as it is created...am I correct?
Really depends upon your attributes and pricing....
Most are assigned singly

Example:
Option name = RAM
Vaues = 2GB, 3GB, 4GB

Same options can be used as options for DDR or DDR2 panels with different pricing