The speed of a site is determined by two things, the size of a page and the loading methods of that page.
Making improvements to either of these areas will help your shop load faster for your customers.
1. Reducing page size
Each time a page is viewed on your the browser needs to load various code and image files.
Smaller files will load faster on the page.
Having fewer files overall also helps.
Potential speed fixes:
Make image files smaller
Make code files smaller
Remove unnecessary page content
Remove unnecessary code files
Reduce duplicate code
Size-based speed fixes are the most straightforward way to improve the speed of your shop.
There is no risk of slowing down your shop with these fixes since smaller files will always load fast than larger ones.
Please note, that speed metrics are complex and are not always useful for benchmarking speed fixes.
Read more about measuring your speed here: How should I measure my speed?
2. Changing loading methods
A website can be developed using methods that make a page load faster or appear to load faster to users by loading files in a methodical order.
Potential speed fixes:
Lazy loading images
Using non-render blocked JS
Caching your site
Making fewer server requests
These fixes are more difficult to implement and typically require custom development work.
Since these fixes can be more costly we recommend that you consider your business objectives before implementing these speed fixes.