Improve visibility and sales

Hello,

We are quite new with Shopify and would like to have direction in how to fill in de Product “card” in the best possible way.

For SEO, what are the most important fields to set up in your “product”?

is it?
-Title

-description

-category

-search engine listing

is it important to use the same words/lines/description in all these fields? or can they be different?

Is it important for SEO to name photos in Shopify as wel as adding the “alt text”. Same words/line as Productname?

How/where can I check if my SEO is working? How can we increase sales with SEO? Which search engines are the best to use to check keywords?

Thank you so much for your help!