When to use this prompt
When launching a new landing page and wanting to maximize conversions.
When iterating on existing landing pages to improve performance.
When teaching a team how to implement A/B testing effectively.
When establishing data-driven optimization practices for your marketing funnel.
The prompt
Create a step-by-step guide on how to use A/B testing to optimize the design of a [type of product] landing page.
The guide should include:
Key elements to test (headlines, CTAs, images, copy, layout)
How to design and run experiments effectively
Tips for analyzing results and identifying winning variations
Best practices to ensure reliable, statistically significant insights
How to iterate and continuously improve landing page performance
Variables to replace:
Real-life example of how to use this prompt
To start, let’s assume I’m a senior marketer at HubSpot. The prompt in the context of HubSpot would look like:
As you can see, this example demonstrates how the prompt structures a comprehensive, actionable guide for systematically testing and optimizing landing page design to improve conversions.

Example output from ChatGPT for this prompt
And here's the output:
Below is a clear, practical, and SaaS-focused step-by-step guide for running effective A/B tests on a landing page design to improve conversions, sign-ups, or demo requests.
A Step-by-Step Guide to A/B Testing a SaaS Landing Page
1. Define Your Goal & Hypothesis
Start with a precise, measurable objective.
Common goals: demo bookings, free-trial sign-ups, email captures, pricing page click-through.
Form a hypothesis:
Example: “Changing the headline to emphasize value over features will increase free-trial sign-ups by at least 10%.”
A clear hypothesis helps avoid random testing and ensures design changes are tied to desired outcomes.
2. Identify the Key Elements to Test
Focus on components that influence user behavior. Typical landing page elements to A/B test include:
Headlines
Value-driven vs. feature-driven
Short punchy headline vs. longer descriptive version
Tone: authoritative, friendly, benefit-focused, or technical
CTA (Call-to-Action)
Button text (“Start Free Trial” vs. “Try It Free for 14 Days”)
Button color, shape, or placement
Single CTA vs. multiple CTAs throughout the page
Images & Visuals
Product screenshots vs. interactive animations
Hero images with people vs. product-only
Video demos vs. static images
Copy
Long-form vs. concise value propositions
Feature-heavy vs. benefits-heavy messaging
Social proof placement (testimonials, reviews, logos)
Layout & Structure
One-column vs. two-column layout
Above-the-fold content order
Placement of forms, trust badges, or pricing snippets
Only test one variable at a time per experiment to isolate its effect.
3. Prioritize What to Test
Not all tests are equal. Prioritize based on:
Expected impact (headline > small design tweak)
Traffic volume (important for reaching significance)
Ease of implementation
Alignment with your main metric
Use an ICE or PIE scoring model if you need structure.
4. Create Your Variations
Design version B so that it differs from version A only in the element you want to test.
Tips for clean variation design:
Keep color palettes, brand identity, and fonts consistent unless they’re the tested variable.
Mock up changes in wireframes before full implementation.
If testing copy, avoid simultaneous design changes; keep formatting identical.
5. Set Up & Run the Experiment
Use A/B testing tools such as Google Optimize alternatives, Optimizely, VWO, HubSpot’s built-in A/B tools, or LaunchDarkly (for feature flags).
Key steps:
Split traffic evenly (50/50 or weighted if needed).
Ensure correct targeting
New visitors only vs. all visitors
Geographic or device segmentation (if relevant)
Avoid test contamination
Use sticky sessions so users don’t see both versions.
Pre-define test duration
Avoid stopping early due to noise.
As a rule of thumb: run for at least 1–2 business cycles (7–14 days).
6. Ensure Statistical Reliability
To avoid false winners, follow best practices:
Sample Size
Use a statistical significance calculator to estimate the minimum sample size needed.
Don’t start analyzing until you reach that number.
Significance Level
Aim for 95% confidence for reliable results.
Avoid Peeking
Checking results too early increases the risk of statistical error.
Use a fixed-horizon test or sequential testing model if your platform supports it.
Control External Variables
Avoid testing during major traffic spikes (holidays, campaigns, outages).
Always run tests concurrently, not sequentially (e.g., don’t test Variation A this week and B next week).
7. Analyze the Results
Once the test reaches significance:
Look Beyond Conversion Rate
Examine:
Click-through rate on CTAs
Scroll depth
Time on page
Lead quality (very important for SaaS—MRR or PQL downstream impact)
Segments (device type, channel, new vs returning)
Check for Confounding Factors
Differences in traffic sources
Seasonal trends
Outliers such as bot spikes or sudden email blasts
Validate Practical Significance
Even if Variation B shows +3% conversion with significance, ask:
Is the lift meaningful for your business?
Is it consistent across segments?
8. Implement the Winning Variation
If the variation truly outperformed:
Roll it out to 100% of visitors.
Document what worked and why.
Share insights with design, product marketing, and growth teams.
If no version won (null test), analyze why:
Was the change too small?
Was traffic insufficient?
Was the hypothesis flawed?
Null results still guide future tests.
9. Iterate & Test Again
A/B testing is a continuous process, not a one-off activity.
Ways to keep improving:
Use insights from previous tests to inform the next hypothesis.
Test deeper into the funnel (sign-up flow, onboarding, pricing page).
Move from single-element tests to multivariate tests once you know the basics.
Re-test occasionally because user behavior changes over time.
Example iteration loop:
Test a headline → winning version focuses on value.
Update subheadline and hero copy to reinforce value.
Test CTA copy that aligns with the value theme.
Test product image that illustrates that value.
Measure aggregate improvement from all tests.
Or to be more specific:

Pro tips
Test one element at a time for reliable results.
Run experiments long enough to reach statistical significance.
Track key metrics like CTR, conversion rate, and bounce rate.
Document results and iterate quickly to continuously improve performance.
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