Conversion rate optimisation (CRO) is the structured process of increasing the share of visitors who take the action a page exists for, such as enquiring, booking or buying. It works by finding out why people do not act, fixing those reasons and measuring the effect, rather than redesigning pages on instinct.
How conversion rate optimisation works
A sound CRO programme runs as a loop:
- Measure. Confirm that conversions are tracked correctly and establish the current conversion rate by page, channel and device. Optimising on broken data is common and wasteful.
- Research. Use numbers to find where people leave: funnel reports, landing page reports, form analytics. Then use observation to find why: session recordings, a heatmap, short on-site surveys, conversations with the people who answer the phone, and usability testing with real users.
- Form a hypothesis. A written hypothesis links an observation to a change and a predicted result: “Visitors on mobile cannot see the price before the form, so showing it in the first screen will increase quote requests.”
- Prioritise. Rank ideas by likely impact, confidence and effort. Fix outright faults straight away.
- Test or implement. With enough traffic, run an A/B test. With too little, make the change and watch the numbers carefully over a longer period.
- Learn. Record what happened and why you think it happened, including the tests that lost.
Why it matters
CRO raises the return on traffic you already have. If your ads, SEO and email bring in steady visitors, a page that turns more of them into enquiries lowers the cost of every lead without spending more on media. For businesses in competitive UK markets, where clicks cost several pounds each, that can be the difference between a channel paying for itself and not.
It also exposes problems that marketing cannot fix: unclear pricing, slow quote responses or a checkout fault on one browser. Fixing those helps every channel at once.
Two UK points shape the work. Analytics on sites with a PECR cookie banner sees only visitors who consent, so test results rest on that sample. And tactics that push people with false urgency, hidden costs or confusing opt-outs are increasingly treated by the CMA and ICO as harmful design, so CRO has to win by making decisions easier, not by tricking people.
Common mistakes
- Testing without research, such as button colours chosen because a blog post said so.
- Running A/B tests on too little traffic. A page with a few hundred visits a month and a handful of conversions cannot reach a reliable answer in a sensible time.
- Stopping tests early the moment one version pulls ahead, which produces false winners.
- Optimising for the wrong conversion. More form fills are not a win if the extra leads never buy.
- Copying competitors’ pages without knowing whether their version works for them.
- Treating CRO as a one-off project instead of a habit.
How to act on it
Start with tracking. Check that every enquiry, call click and sale is recorded once, and only once. Then choose the page with the most traffic and the most commercial value, often a main service page or the landing page for your biggest campaign, and research it properly before changing anything.
For smaller UK businesses, the best early gains usually come from fixing obvious faults rather than testing: unclear headlines, missing prices, broken mobile forms, slow pages, and calls to action that do not say what happens next. Run proper tests once there is enough traffic to support them. Google Optimize closed in 2023, so testing now means a dedicated tool such as VWO or Optimizely, or a testing feature built into your website platform.
Much of this is built in from the start when I design landing pages for ad campaigns: the tracking, the research questions and the first hypotheses are set up before any traffic arrives.