One of our biggest challenges creating a B2B ecommerce store was making it abundantly clear the products were not for customer purchase, while making it extremely alluring to businesses to place their orders. Some of the essential requirements for White Label Bath & Body were: 

Creating clear solutions for purchasing samples vs wholesale products 
Creating different maximum and minimum order quantities for products
Creating a simple, self explanatory UI and UX
Turning a complex system into an easy intuitive process for businesses
Easily adding in new products and ranges
Illustrating the products selling points efficiently
Upselling, cross selling, and bundling with ease
E-mail list building strategies
Increased quality of UI design