Here you can digest how to use Wikipedia in bite-sized morsels. The tips listed below were created for the Tip of the day project, or the Styletips project, but are listed here by title and organized by subject area for your convenience.
When using tables in articles, consider using class="wikitable" at the top of the table, like so: {| class="wikitable". This puts a grey border around all the cells, gives heading cells a grey tint, and uses many other common formatting settings without having to spell them all out.
Here are additional resources suitable for new as well as expert contributors: