Getting the user experience right can be the best growth hack of them all. http://blog.usabilla.com/a-growth-hackers-perspective-on-ux/

Examples:
https://www.webbyawards.com/winners/2016/advertising-media/features/best-user-experience/

Color selection:
https://medium.muz.li/the-ultimate-ux-guide-to-color-design-4d0a18a706ed?token=H46KrLXIZqV1Sm-Y