Every extra second of load time reduces conversion rate by roughly seven percent. In a store doing 100,000 SEK per month, that's 7,000 SEK lost. And WooCommerce is heavy by default, so optimization isn't optional.
Hosting
The fastest way to speed up WooCommerce is better hosting. Shared hosting can't handle WooCommerce with more than a hundred products without it showing. At minimum a VPS with 2 GB RAM, preferably managed WordPress hosting like Kinsta or Cloudways.
Object cache
Redis object cache reduces database queries dramatically. WooCommerce makes hundreds of queries per page load. With Redis, results are cached in memory. Install the Redis server, activate the WP Redis plugin. Measurable difference, especially on category pages with many products.
AJAX cart fragments
WooCommerce loads cart data via AJAX on every page (to show product count in the header cart). It's the single most performance-heavy feature. Disable Cart Fragments plugin turns it off, but then the cart icon doesn't update dynamically. Alternative: cache the fragment aggressively.
Image optimization
Product images in WebP, lazy loading on everything below the fold, right dimensions. ShortPixel or Imagify converts automatically. It halves image weight without visible quality loss.
Measure
Google PageSpeed Insights and GTmetrix. Check especially Largest Contentful Paint (LCP) and Time to First Byte (TTFB). Measure product page, category page, and checkout page separately. They often have completely different performance profiles.
Do one thing at a time. Measure before and after. Otherwise you don't know what actually helped.