If you have a large number of products on your Google Shopping campaign, either as a large number of individual brands, or a large number of products by one individual brand, it’s more important to segment your products. The best way to do this is by segmenting brands using custom labels. Create labels for High and Medium profitability products, this will allow you to easily identify the products you need to bid higher on.
If you supply a large number of products from a small number of brands, for example, you sell Dulux Paint, but there are hundreds or thousands of products in this range, you can further segment them. In this instance you could add a new field to your Shopping Feed for “custom_label 1”, and in this field further segment your products, by, for example, colour. You would then have 1 ad group for “Dulux”, 2 product groups for “Low” and “High” profitability, and the 2 product groups will again be segmented by “Red, White, Grey, Black” etc.