7 e-commerce mistakes that quietly cost online stores sales

Symptom: ad spend goes up, sessions go up, revenue per session stays flat or falls. More visitors to a store that loses most of them in the same place multiplies the loss.

Fix: find the funnel step with the biggest drop-off before scaling a campaign, and fix that first. A store that converts 2.4% instead of 2.0% gets 20% more orders from every euro of advertising. Our conversion rate optimization guide shows how to find the step.

Symptom: “our conversion rate is 1.8%, is that good?”, with no breakdown. A blended number hides a broken mobile checkout behind a healthy desktop one, or a strong email channel behind weak paid social.

Fix: track add-to-cart, checkout start and checkout completion rates by device and channel, and compare each with the same period last year. Published averages vary more than threefold for the same category, so your own history is the benchmark that matters.

Symptom: a large drop between cart and completed order, and support questions about delivery costs. In Baymard's survey, 40% of shoppers who abandoned for a reason other than browsing cited extra costs, and 12% could not see the total cost up front.

Fix: show delivery costs on product pages, a total in the cart before any personal details are asked for, and a free-shipping threshold if your margins allow. Our cart abandonment guide covers the full list of checkout fixes.

Symptom: low add-to-cart rate on specific products, and repeated questions to support (“how big is it?”, “does it fit…?”). In Nielsen Norman Group's e-commerce studies, 20% of task failures (shoppers who did not complete a purchase) were caused by incomplete or unclear product information. Baymard found that 42% of users try to judge a product's size from its images.

Fix: give every product a full image set including an in-scale shot, complete specifications in a consistent format, and a description that answers who it is for. See our guides to product pages, product photography and product descriptions.

Symptom: sales spike during promotions and collapse between them; margin shrinks every quarter; customers ask “when is the next sale?”. Constant discounting trains customers to wait and attracts the buyers least likely to return.

Fix: compete on the things that make full price acceptable, such as clearer products, faster and dated delivery, easier returns, and proof from other customers. When you do discount, in the EU the reference price must be the lowest price of the previous 30 days, so artificial “was” prices are not an option.

Symptom: a minimal, beautiful store that looks like a famous brand's and converts far below it. Large retailers can show one photo and a short description because shoppers already know and trust them.

Fix: a less-known store must earn trust on the page itself, with company details, reviews, visible policies, familiar payment methods, and product content good enough to prove the product is real. Our trust signals guide covers what to add.

Symptom: a return rate treated as a logistics cost rather than a content problem. The NRF and Happy Returns estimate that 19.3% of online sales were returned in 2025, compared with 15.8% of all retail sales.

Fix: record a return reason for every return and read them per product. “Smaller than expected”, “colour different from the photos” and “not as described” are product-page failures you can fix with an in-scale image, colour-accurate photography or a clearer size guide. Every return avoided is a sale kept and a shipment saved.