Good sources on how to properly build frontend?

Hello r/webdev! I'm a junior web developer, and I recently got my first job. I thought, I was doing fine for a starting position and my improvements were going steady, until I've read this article - https://www.freecodecamp.org/news/i-reviewed-fifty-portfolios-on-reddit-and-this-is-what-i-learned-e5d2b43150bc/ . It points to the majority of my mistakes in design and accessibility(mobile scaling, keyboard navigation, cookie cutter design).

Is there any good source or guidelines on how to properly build a good website, so I don't have to comeback later and add media queries with max-width, and other fixes?