To read cookies using JavaScript, developers can use the document.cookie property to access cookie data and enhance web functionality. Cookies are small data snippets stored in your browser by websites, commonly used for remembering login sessions, tracking browsing activity, and storing preferences. To create a cookie, you can use the document.cookie property, while to read a cookie, you can split the document.cookie string into individual cookies using JavaScript's built-in methods. Best practices when reading cookies include using encodeURIComponent and decodeURIComponent to handle special characters safely and avoid data corruption, avoiding storing sensitive data in cookies, updating or deleting cookies properly, especially session-related ones, and ensuring secure and efficient session management.