Here are a few of the ways by which you can optimize your website:

Use your category navigation well.

This is related to the previous point: people must be able to find what they need quickly. It is common to list everything in one category. You need to categorize products in the same way as different sections of a book store. 

It is important to use the most common terminology and terms used by others. You can use sites like Vishion to help you categorize your goods on Shopify.

Do not try to sell everything on one page

Your site will look messy and frustrate your customers if you have too much information or items on one page. Everything is important when it is all there. Avoid the kitchen sink approach at any cost. 

This is not the best way to optimize your online store. Keep in mind that if they already visit your site, they will use the navigation to find the products they are looking for. Allow them to browse your shop with ease.

Do not force your customer to sign up

If you're already a highly respected site, you can't force people into signing up to access your site. To purchase goods in retail stores, people don't need to register as members. Online shops shouldn't be any different. Online stores should function as seamlessly as traditional retail.