After building a few websites, I thought of looking for guidelines or industry best practices to illustrate the shoulds and shouldn’ts in building a website. The first place I searched was FCC’s forum, and I didn’t find any which was interesting because the curriculum can definitely be improved with it.
I found Google HTML/CSS guide: http://google.github.io/styleguide/htmlcssguide.html
On top of making websites responsive, and mobile-friendly etc. Feel free to add any standards/guidelines you adhere to when making a website.