Documenting best practices

[egekorkan]

Regarding your question " or a more general section on best practices for TD design.". I feel that we have similar stuff in multiple places. Going forward, I think we can think of adding some tags for HTML elements that can be best practices. Like the implementation report, we can extract such best practices as a separate document for implementers. It can be a separate section but I fear that many texts can be too detached from their context.

Originally posted by @egekorkan in #2018 (review)