If you want users to click something, make it stand out. If your site or app uses a lot of blue, users probably won’t notice a blue button right away, just …
against a light background. Users much more likely to …tice a blue button right away, just like a light button won’t stand out against a light background. Users much more likely to click a CTA button that strongly contrasted with the background.
Even though they originally predicted the green button would perform better, the red button resulted in 21% more clicks.