After auditing 40+ Shopify stores doing $100K-$500K/mo, the same three conversion killers show up almost every time.

1. Shipping surprise at checkout

If your shipping cost shows up for the first time on the checkout page, you're bleeding 15-25% of carts. The fix isn't free shipping — it's showing the cost earlier. Add an estimated shipping calculator on the product page or cart. One client went from 2.1% to 3.4% checkout conversion just from this.

2. Too many form fields on mobile

Most Shopify themes still default to 8-12 checkout fields on mobile. Every extra field costs ~4% of completions. Use Shop Pay or accelerated checkout to skip the form entirely. If you can't, at minimum remove "Company name" and "Apartment" unless your AOV demands it.

3. No post-add-to-cart momentum

After someone clicks "Add to Cart", you have about 8 seconds of peak purchase intent. If your store sends them to the cart page and makes them click "Checkout" again, you're adding friction at the worst possible moment. A slide-out cart with a direct checkout CTA converts 10-18% better in every test we've run.

These aren't complicated fixes — they just require someone paying attention to the data. That's what we do at CartScale for brands ready to stop leaving money on the table.