Optimise and Compress Images = Apps to use are Crush Pics or Image Optimizer
Remove Apps you don't use - Check to see if you have 2 or more of the same apps and remove e.g Klaviyo and Shopify Email
Download a Fast and Responsive Theme for Your Shopify Store - Look for a fast and responsive theme and make sure you are on a 2.0 theme and check how it's performing by using Heat Maps. More info here...
Minimise Redirects and Broken Links = In Shopify, you can apply 301 redirects by the built-in redirects function called “URL redirect.” For broken Links use this...
Use Hero Layout Instead of Using Sliders - Instead of a slider, use a single, high-quality Hero Layout image with a clear call to action.