A/B testing, sometimes called split testing, is a simple idea: show version A to half your visitors and version B to the other half, then see which one performs better on the goal you care about. It replaces opinion with evidence.
What you can test
- Headlines and value propositions.
- Call-to-action buttons, wording, and placement.
- Page layouts and which sections come first.
- Email subject lines and send times.
One honest caveat
You need enough traffic and enough patience for the result to mean anything. Calling a test after a handful of visitors is how people fool themselves. On low-traffic pages, I often rely on best practices and clear thinking first, and save testing for the pages that get real volume. It pairs closely with conversion rate optimization.