Alex Sexton, on his personal blog:
This list is the product of many years of experience in the front-end web development field. I maintain this list as a reminder to myself to always follow best practices, and to not compromise on performance, even if I’m in a time crunch. I read it before I start any project, and share it with my team at work (sometimes we joke and call them “codemandments”) so we can all be on the same page and do our part to keep the web fast.
He goes on to say "feel free to fork this for your own use," so use this liberally. Some of my favorites:
I will use SVGs instead of JPGs, wherever possible.
I will resist the urge to use window.alert to inform visitors that there’s a Facebook group for cool friends and if they wanna join it, that’s fine, it only takes a few clicks. 😂