Some Best Practices For Handling Errors In JavaScript:

1. Use try...catch blocks: This is the most common way to handle synchronous errors. It allows you to "try" a block of code and "catch" any errors that occur.

try {
    // Code that may throw an error
} catch (error) {
    // Handle the error
}

1. Throw your own errors: If you detect a condition that could cause problems later, you can throw your own error with the throw statement.

if (someCondition) {
    throw new Error('This is a custom error message');
}

1. Use Promise.catch() for asynchronous errors: Promises are a common way to handle asynchronous operations in JavaScript. If an error occurs in a promise, it can be caught with .catch().

someAsyncFunction()
    .then(result => {
        // Handle the result
    })
    .catch(error => {
        // Handle the error
    });

1. Always deal with errors: Never leave a catch block empty. Even if you think an error can't or won't occur, it's still good practice to handle it.

2. Use error-first callbacks: In Node.js, it's common to use callbacks to handle asynchronous operations. The convention is to make the first parameter of the callback an error object. If there is no error, the first parameter will be null.
   

fs.readFile('somefile.txt', (err, data) => {
    if (err) {
        // Handle the error
    } else {
        // Handle the data
    }
});

1. Use a logging service: It's important to keep track of errors that occur in your application. A logging service can help you do this.

2. Don't suppress errors: Unless you have a very good reason, don't suppress errors by simply logging them and not re-throwing them or passing them along. This can make debugging very difficult.

3. Use finally blocks: finally blocks can be used to clean up after your code, whether an error occurred or not.
   

try {
    // Code that may throw an error
} catch (error) {
    // Handle the error
} finally {
    // Cleanup code
}

1. Understand the different types of Error objects: JavaScript has several built-in error constructors, such as Error(), RangeError(), TypeError(), and more. These can be used to throw more specific types of errors.