In most Shopify stores collections exist to fill the navigation menu. That is a missed opportunity, because the majority of organic demand is category-level: people search "womens leather tote", not a specific product name or SKU.
This makes the collection page the most valuable SEO asset in the store. A product page competes for one product; a collection page competes for a whole family of queries — and it is the page most stores leave empty apart from a grid.
Menu logic and search logic are different
Navigation is built for browsing and is deliberately kept simple. Search is far messier: the same group of products attracts dozens of phrasings. Creating collections that do not appear in the menu but answer real queries is entirely legitimate.
The practical method: list the questions customers ask you, and pull your internal site-search logs. Those logs are the closest thing you have to a free keyword tool for your own catalogue.
Every collection needs real copy
Aim for 150–200 words of genuine text above or below the grid. Not a keyword list nobody reads — an introduction that explains how to choose within this category. Written properly it works twice: it gives the page context for search, and it helps the undecided visitor buy.
Too many collections is also a problem
Creating a collection for every variation backfires. Near-identical pages compete with each other and none of them wins. The test is simple: if you cannot write genuinely different copy for two collections, they should be one.
Filters are not collections
Faceted URLs generate infinite combinations and burn crawl budget. Single-dimension filters that people actually search (colour, size) can be indexable; multi-facet combinations should not be. Point their canonical at the parent collection and keep them out of the crawl.
Where a filter combination attracts steady demand, promote it to a real collection with its own copy rather than trying to get the filtered URL indexed. That is the more durable fix.
Internal linking starts here
Link from articles to the relevant collection, and from parent collections down to children. Use the destination name as the anchor text — "womens leather totes", not "click here". Both the reader and the crawler should know what they are getting.
Get the hierarchy right early
Restructuring collections later means changing URLs and managing redirects. Setting up a shallow two-level hierarchy before the catalogue grows avoids one of the more expensive jobs in ecommerce SEO.