Alexander Pann, a long-time MPS enthusiast, has collected and, more importantly, organized the available knowledge on MPS on a nice website, MPS Platform Docs. You will find there many answers, tips, and links to resources on various topics related to MPS development, from language design to debugging to UX.
Alexander often links to my website as well, but MPS Platform Docs is infinitely better to browse because it is organized by topic. I hope you will find it helpful and I am grateful to Alexander for providing it.