stuck on getting shopify to rank for keywords

Most people try to rank product pages, but for anything commercial it's usually the collection pages that rank. Write a proper title and description in the "search engine listing" section at the bottom of each collection, and add a short paragraph of real text on the page itself, a collection that's only a product grid doesn't give Google much to go on. What kind of products? Some niches are just dominated by amazon and the big brands, and then long-tail terms are the only way in.