Which to use: Product or Child or Catagory or Custom Field ??

[raam]

Hello everyone.
My question may seem very ridiculous but I'm a bit confused with the terminology and uses. Of course I did some searches but found more detailed explanations in how to implement them, not about which to use. Basically I have some products with choices and not sure which to use (Procucts, Child Products, Custom Fields or Categories) for each one ??

I have 4 things to sell:

Shirts/Pants/Hats/Belts

They all are available in different colors:

Brilliant/Tropical/Urban/Rustic

They are available in different sizes:

Small/Medium/Large/XL/XXL

Haha, so I guess I'm simply asking how to set them up using Vm's different sections. Sorry for the newbie question ... UGH !

Thanks