There are two options for recommending products in your cross-sell item block: Manual and Shopify Recommendations.
Shopify Recommendations
Some themes have recommended products sections that display complementary and related products to customers on your product pages and in your cart.
These recommendations can be customised using the Shopify Search & Discovery app.
A recommended product displays in the cart only if the following criteria are met:
It isn't sold out (for related products, the product can also display if continue selling when out of stock is activated; for complementary products, the product must have inventory above 0).
It doesn't have Unlisted product status.
It has a price higher than $0.00.
It isn't a gift card.
It is published to your Online Store sales channel.
It isn't currently in the visitor's cart.
Install the free Search & Discovery app and setup your Complementary products for each item here:
Then in the Cross sell settings, select Shopify Recommendations and complementary:
You can choose which products to show recommendations for and how many to display.
This is the most streamlined way of setting up targeted cross-sells in your cart.
Manual Recommendations
The benefit of manual recommendations is that you control the exact products that are shown. This is a good option if you have up to 3 items you want to create cross-sells for, anything more and it starts to get complex and you should setup Shopify Recommendations.
To set this up, go into your Cross Sell settings.
In the Block settings section, make sure 'Specific Products' is selected for 'products to cross sell' then add the products in using the browse/search drop down.
Recommended Product Settings - display and styling
There are TWO ways to display your cross-sells: Stacked and Inline.
Stacked looks like this:
With Stacked, items are shown on top of each other.
Inline looks like this:
Items are shown in a side scroller.
FAQs
Can I add a discount to the cross-sell item?
Yes, you can. What you need to do is setup a discount in your Shopify Discounts (not in the Unicorn app) and make a Buy X Get Y for the cross-sell you want to offer.
E.g. Buy Product A and get 20% of product B.
You can then offer the Cross-sell (product B) in the cart and change the title to 'add me and get 20% off' and then the customer can benefit from this offer.