The product page is where the decision happens. Everything before it brings people there and everything after it processes an order they already decided to place.
Most product pages fail on the same few things, and none of them are design.
Answer the questions that stop a purchase
A customer who cannot find one piece of information leaves. The information is usually the same set.
Size, dimensions, weight, materials. Not in a table nobody wrote. The actual numbers.
What is in the box. Particularly when it might not include something obvious.
Delivery cost and time, before checkout. Unexpected shipping cost at the final step is the most commonly stated reason for abandoning a cart, and showing it here prevents it. Checkout optimization walks through the rest of that path.
Returns. One line and a link. A visible returns policy removes the risk a first-time customer is weighing.
Write the description for the person, not the search engine
Manufacturer text copied across every retailer selling the same item is duplicate content and is also useless. It tells the customer nothing they cannot read elsewhere.
Write what you know: who it suits, who it does not, how it compares to the other one you sell, what people ask about it.
That last one is the most valuable and the easiest to obtain. The questions arriving by email are the paragraphs missing from the page.
Images: several, honest, and sized properly
More than one, from different angles, including something showing scale. A product photographed alone against white is impossible to judge the size of.
Resize before uploading. A camera-resolution image displayed at 800 pixels wastes the difference on every visit, and a product page is where speed converts directly into orders. Optimizing images goes into the sequence.
If variations change the appearance, give each its own image so selecting a colour shows that colour. Setting up variations goes into attaching them.
Say what stock you have
"In stock" and "out of stock" are the minimum. Showing a low quantity when it is genuinely low is honest and it converts.
What matters more is that it is accurate. Selling something you do not have costs a refund, a complaint and the customer, and the usual cause is stock tracked at product level rather than per variation, so the shop knows you have twelve without knowing which sizes. There is more on the setting in inventory and stock management.
For out-of-stock items, offer a notification in place of a dead end. That converts a lost visit into an email address.
Reviews, including the imperfect ones
Reviews answer the question the description cannot: what it is like once it arrives.
A product with only five-star reviews reads as filtered. A mix, with a reply from you to the critical ones, reads as real, and the reply is often more persuasive than the review.
Ask for them: a message a week or two after delivery, with a direct link. Nobody navigates back on their own.
Structured data, done accurately
Marking up price, availability and rating lets search results show them, which affects whether your listing is clicked.
It must match the page. A marked-up price that differs from the displayed one, or availability that says in stock when the page says otherwise, is worse than no markup; it is inaccurate structured data, and that is treated as such.
Most shop plugins generate it. Check the output rather than assuming, particularly after a theme change.
Related products, chosen rather than automatic
Automatic related products are usually category neighbours, which is a weak reason to show something.
Set them deliberately where it matters: the accessory this needs, the size up, the thing customers actually buy alongside it.
Keep it to a few. A page ending in twenty thumbnails is a page inviting the visitor to start over rather than buy.
Speed matters more here than anywhere
A slow category page loses browsers. A slow product page loses buyers, who arrived with intent.
Product pages are also the heaviest on a shop: many images, variation data, reviews, related products, and often a gallery script. A product with fifty variations loads fifty extra records before rendering. For reducing it, see WooCommerce speed optimization.
Test on a real phone on mobile data, which is how most customers arrive.
Make the buy button obvious
Visible without scrolling on a phone, in a colour nothing else uses, with a label saying what it does.
Then remove what competes with it. A page with three equally prominent buttons has no primary action, and the visitor picks none of them.
Find your own weak pages
Rather than improving every page, find where customers leave.
Compare views to add-to-cart rate per product. A product with many views and few additions has a page problem: usually a missing answer, a bad photograph, or a price that needs context.
That comparison points at the specific page worth an hour, which is more useful than a general improvement pass. For where the numbers are, see reading WooCommerce analytics.
Find which pages are actually losing sales
Improving product pages generally is slow; improving the ones that receive traffic and produce nothing is fast.
awk '$7 ~ /\/product\// {print $7}' ~/logs/example.com | sort | uniq -c | sort -rn | head -15
wp db query "SELECT p.post_title, COUNT(oi.order_id) c FROM wp_posts p
LEFT JOIN wp_woocommerce_order_itemmeta im ON im.meta_key='_product_id' AND im.meta_value=p.ID
LEFT JOIN wp_woocommerce_order_items oi ON oi.order_item_id=im.order_item_id
WHERE p.post_type='product' GROUP BY p.ID ORDER BY c ASC LIMIT 15;"
The interesting pages are the ones high on the first list and low on the second. Those are products people are finding and not buying, which is a page problem rather than a demand problem.
Work through those individually rather than applying a general improvement everywhere. Ten pages fixed deliberately is worth more than a change applied to a thousand.
Write the answers people actually search for
The questions that stop a purchase are visible in the site's own search log and in the support inbox.
awk -F'[?&]' '{for(i=1;i<=NF;i++) if($i ~ /^s=/) print substr($i,3)}' ~/logs/example.com \
| sed 's/+/ /g' | sort | uniq -c | sort -rn | head -15
Sizes, compatibility, delivery time and what is included account for most of it. Each is a sentence on the product page and each is currently an email somebody has to send before buying.
Answering them on the page removes both the support message and the customers who did not bother to ask.
Check the page on a phone, on mobile data
Most product pages are viewed on a phone and designed on a desktop, and the difference is where the button goes.
curl -s -o /dev/null -w '%{time_starttransfer} %{size_download}\n' https://example.com/product/example/
curl -s https://example.com/product/example/ | grep -oE 'src="[^"]*\.(jpg|png|webp)"' | wc -l
A page weighing several megabytes because of full size images is slow on a connection that is not yours, and the price and the buy button are below several screens of scrolling.
Load one on a phone and count how much scrolling it takes to reach the button. That single observation produces more improvement than most redesigns.