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.
The CategoryTree is a MediaWiki extension that provides a dynamic view: you can change how much you see of a category's structure as a tree. You can use it to show a category and its subcategories by putting the category name between category tree tags like this:
<categorytree>
Trees in religion
</categorytree>
The result is a category tree like the one shown to the right. Click on the triangles to expand and collapse the tree.
ProveIt is a user script (and gadget) that makes it easy to find, edit, add, and cite references in Wikipedia articles.
It provides a graphical interface for editing, adding, and citing references. The ProveIt toolbar displays at the bottom of the Wikipedia text editor (for articles only).