Conversion Rate Optimisation: A Practical CRO Guide

7 min readUpdated June 2025By CTA Flow

Conversion rate optimisation (CRO) is the practice of increasing the percentage of visitors who take a desired action — without increasing traffic spend. For every rupee you spend on CRO, you extract more value from every rupee you've already spent on acquisition. It compounds.

What counts as a conversion

Define it first. A conversion is whatever action you're optimising for: a button click, a form submission, a purchase, a signup. Different pages have different conversion goals. Measure one per page.

The CRO process

Research (what is currently happening?), Hypothesis (what change and why?), Test (A/B or multivariate), Analyse (did it work?), Iterate. Most CRO programmes fail because they skip Research and jump to Testing. Data should dictate the hypothesis, not instinct.

Highest-impact changes to test

Headline copy (biggest lever), CTA button text, CTA placement (above vs below fold), hero image or video vs no image, social proof placement, form length (fewer fields = higher completion), page load speed (every 100ms reduction in load time improves conversion rate measurably).

Sample size and statistical significance

Run tests long enough to reach statistical significance (typically 95%). At low traffic volumes, run tests for at least 2 weeks to account for day-of-week effects. Don't call a winner after 50 visits.

What to do without A/B testing tools

Sequential testing: run version A for 2 weeks, version B for 2 weeks, compare. Not perfect but directionally useful. Or use session recordings and heatmaps to find friction before building a hypothesis.

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