What should I test first in my A/B testing program?

Start testing elements with the highest potential impact and lowest implementation effort. Common high-impact starting points include headline and value proposition (affects all visitors), primary CTA buttons (directly impacts conversions), form length and fields (major friction point), pricing presentation (affects purchase decisions), and checkout process (final conversion barrier). Use data to identify what to test—look for high-traffic pages with low conversion rates, or pages with high drop-off rates. Test one variable at a time initially to understand what drives changes. Example: Testing the main CTA button color and text on a landing page increased conversions by 15%, providing quick win and building testing momentum.