Know whether you have enough traffic
Detecting a small difference requires many visits and many conversions. A page with a few hundred visits a month and a handful of inquiries cannot reveal a ten percent improvement. Random swings will dominate.
If you have little traffic, test only big changes, such as a completely different headline or an entirely different offer, or use before-and-after comparisons with caution. Otherwise rely on user feedback and common sense.
A rough rule: if a page gets fewer than a few dozen conversions a month, treat any test as a hint rather than proof.
Change one thing at a time
Choose a single variable: the headline, the button text, the form length or the main photo. If you change several at once, you will not know which made the difference. Write down your guess and why you think it will help. That discipline stops you from testing random ideas.
Pick changes with a plausible mechanism: reducing form fields, clarifying the offer, making the phone number more prominent.
Pick a measure before you start
Decide what counts as success: form submissions, calls, booking clicks. Avoid choosing the measure after you see the results. Make sure tracking works for both versions. Test by completing the action yourself on each.
Choose a run length in advance, covering at least a couple of full weeks so weekday and weekend patterns are included, and do not stop the moment one version leads.
Avoid common traps
Peeking early and stopping on a lucky streak is the main source of false wins. Others include seasonal swings that coincide with the test, a promotion running on one variation, and traffic from different sources reaching different versions.
Do not test during unusual periods such as holidays or a big ad push. Keep notes of anything else that changed on the site or in marketing.
Read the result honestly
If one version wins by a wide margin over enough conversions, adopt it. If the difference is small, treat the test as inconclusive and choose the version that you believe serves customers better. A flat result is information too: it tells you that this element was not the problem.
Free or low-cost testing tools exist, but some add scripts that slow pages or flicker. Check that the tool does not damage speed or search appearance.
Write down what you learned in a shared file, including tests that failed. Those notes stop a future employee or designer from repeating the same experiment.
Use other forms of testing as well
Watch five people try to use your site, or run a short session with a customer, and you will learn faster than from a statistics dashboard. Read form submissions for confusion, ask callers what nearly stopped them from calling, and review recorded sessions if you have them. Combine this with occasional tests on the pages that matter most, such as your homepage and contact page, and record each result so you do not repeat the same experiment.
Common questions
How long should a test run?
At least two full weeks, and longer for low traffic. Decide the length before starting.
Can I test two pages by running ads to each?
That is possible, but ensure the audiences are the same and the budgets equal, otherwise differences may come from the ads, not the pages.
This guide is general information. Search engines change how they work and their guidelines; check Google's current documentation for your situation. Nobody can guarantee a ranking.