If we understand correctly, two post types involved in similarity search: your Custom Post Type called Listings, and normal posts.
There are two main possibilities to increase the number of similarity hits:
1. increase the similarity between posts (any post types)
2. and reduce the similarity threshold
1. Increase the similarity between posts
You have to think over and find the common points between these two post types before you configure WordPress and our plugin.
Common points can be similar words in titles or content, common categories, or the special „WRI Similarity Marker Category„ that is especially used for creating similarities by assigning more different types of posts to the same category.
For example, you should not only assign Listings (your special post type) to “BizCategories” and “BizArea” categories, but assign normal posts to these two categories.
And / or you can assign the elements of these two post types to the WRI Similarity category.
You can setup which existing category would like to use in case of which post type on “Related Types” tab on WP Related Items Settings page.
WRI Similarity Maker Category can be enabled on “General” tab.
Manual assignment of specific any type of post items is also possible, if you would like to explicitly order to each other some items. It is available on edit pages of every post (any post type). “Enable manual settings of WRI relationships” option should be checked in if you would like manually assign items.
You can use similar words in title or content.
2. Reduce the similarity threshold
Similarity threshold should be adjusted to the level of similarity you can reach using the assets above.
If similarity hits are low, or there are no similar items, similarity threshold should be reduced.
This can be done on YARPP settings page (there is a global parameter for all post types), or you can adjust it on “… Page” tabs of “WP Related Items” options panel. In the letter case you can set the threshold separately for every “displayed post type TO related post type” pair.
Important: After you change WP Related Items settings, you may need to save YARPP settings also in Settings -> Related Posts (YARPP) menu, to refresh them. So please push “Save Changes” button on “Related Posts (YARPP)” options page.
We hope this guidance will help you.
If you have any more question or need help, please contact us.