On the product page

There are several types of cross-sell sections that you can add:

 

Obviously, don’t add all these sections : ) Choose what makes the most sense for your store.

 

Relevant recommendations

Relevancy is what matters most here. Make sure that what you’re recommending is highly relevant for them, based on the product they’re looking at now, and if possible, based on their browsing and/or purchasing history.

 

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See also best practice #87) Offer relevant compatible products on the Product page