There are a number of ways to improve your web browser to make it a more effective Wikipedia tool:

• install plugins
• install user customized JavaScripts (a simple cut/paste operation) into your user page's vector.js or monobook.js skin. Installing to your common.js subpage will allow both skins to use a single JavaScript installation.
• add pre-saved bookmarks to your favorites
• add bookmarklets to your favorites or to your browser's toolbar

As you can see, tools are implemented in a number of ways. There are tools available for many different purposes, and with many different functions, and some that are multipurpose. Many of these are explained at Wikipedia:Tools/Browser tools, which includes a list of tools, for each major browser.