Quick answer
CRO is a diagnostic and testing process: define the conversion, segment visitors, identify the bottleneck, form a hypothesis, implement a meaningful change and measure the business result.
Do not optimize the average website blindly. A landing page for paid search may need a different treatment from an informational article or returning customer page.
What I would check first
I would inspect traffic source, intent, headline/message match, proof, call-to-action visibility, mobile friction and form completion. Then I would compare the recorded conversion with actual lead quality.
If a page already converts reasonably well, I would look for the biggest evidence-backed opportunity rather than running random tests. The purpose of testing is learning, not generating activity.
Decision framework
Use the sequence Clarity → Relevance → Trust → Friction → Motivation → Measurement. Fix the earliest weak point. If visitors do not understand the offer, button colour is unlikely to be the main issue.
For example, replacing a generic 'Submit' button with a clear action and adding relevant proof can be a more meaningful hypothesis than changing a page's background colour.
Implementation steps
Establish baseline conversion and quality, document the hypothesis, make one meaningful change, define the observation window and record the result. Where traffic volume permits, use controlled experiments; otherwise use disciplined before-and-after analysis and acknowledge the limitations.
Keep a testing backlog ranked by expected impact, confidence and implementation effort. Retire weak hypotheses rather than endlessly recycling them.
Common mistakes and current platform considerations
Avoid declaring winners from tiny samples, testing several unrelated changes at once or using statistical language to create false certainty. Also avoid optimizing for raw form volume when sales quality is the actual constraint.
Consent settings, browser behaviour and analytics configuration can affect observed conversions. A testing program should distinguish a genuine behavioural change from a measurement change.
Measurement and business implications
Track conversion rate, qualified conversion rate, revenue or pipeline per visitor and, where possible, incremental lift. A higher conversion rate is not automatically better if average customer value falls.
Use the Conversion Rate Calculator and Website Conversion Checklist. Link the findings back to the website-leads and website-mistakes guides for diagnosis before the next test.