When working with JSON data in JavaScript, following best practices helps you avoid common errors and keeps your code robust:

• Always validate input data before parsing or stringifying;
• Handle parse errors using try...catch blocks to prevent your application from crashing;
• Avoid circular references in objects, as JSON.stringify will throw an error if it encounters one;
• Sanitize and escape data if it will be displayed on a web page to prevent security issues;
• Use clear and consistent naming conventions for your JSON keys;
• Keep your data structures simple and only include necessary information to reduce complexity;
• When storing JSON in localStorage or sessionStorage, always convert objects and arrays to strings using JSON.stringify and parse them back using JSON.parse;
• Regularly check for potential changes in the data structure, especially when working with external APIs;
• Document the expected structure of your JSON data for easier maintenance and debugging.

There are several common pitfalls to be aware of when using localStorage and sessionStorage:

• Storage size is limited (usually around 5MB per origin), so avoid storing large amounts of data;
• Data stored in localStorage persists even after the browser is closed, but can be cleared by the user or browser settings;
• sessionStorage data is cleared when the browser tab or window is closed, which can lead to data loss if you expect persistence;
• Data stored in either storage is not encrypted and can be accessed by any script running on the same origin, so never store sensitive or personal information;
• Data in web storage is not automatically synchronized across tabs or devices;
• Storing non-string data directly without stringifying can lead to unexpected behavior or bugs;
• Storage events are only triggered in other tabs, not in the same tab where the storage is modified.