Catalog management is something that should be taken very seriously. If you cannot manage the data, everything becomes more complicated once it is out of control. As the number of ecommerce channels increases, structured catalog data management becomes more crucial.
For successful catalog management first thing to invest in is time. More time you spend on structuring your data and catalog, the more conversions you have.
Start with categorizing (StoreAutomator is very good at categorization and lets you create numerous categories.)
Creating custom fields allows you to add product specifications by entering an attribute and a value. You can create custom fields to group your products related to their specifications. It helps you standardize the data.
Shipping the right product is very crucial in ecommerce. Setting up your SKUs properly will prevent this kind of inconvenience. Especially when you are working with multiple suppliers, it would be beneficial to create your own SKU. That would provide easiness for multi-channel product management also.