Wikipedia:Table dos and don'ts

Tables are a great way to present data.
When you work with tables:
DO:
Use wikitables, not HTML tables.
Use class="wikitable" to apply standard style.
Use short, self-explanatory captions and headers.
Use CSS classes, not inline attributes, to set table style.
Make columns sortable as appropriate.
DON'T:
Don't use tables for visual layout.
Don't use color alone to convey information.
Don't nest tables if avoidable.
Don't use scrolling tables in articles.
Don't split up sortable tables.

See also