When designing documents, which will ultimately end up in collections, one way to start off the design process would be to gain an understanding of what outputs (such as printed reports, or data that will be pulled up on a screen at some point). You can then work your way backwards to decide which documents need to be created. As an example, let's take the one shown just now: customers, products, and purchases.
If at some point you need to print a customer report, it might be appropriate to design a customer collection. You should only include information that needs to go into the report. In a like manner, you might have an inventory of products that need to be tracked. You would then design a product collection, including ...
