What steps can be taken to gradually improve and build upon existing PHP code, especially for novice developers?

Issue: Novice developers may struggle to improve and build upon existing PHP code due to lack of experience and understanding of best practices. To gradually improve and build upon existing PHP code, novice developers can start by refactoring code to make it more readable and maintainable. They can also break down large functions into smaller, more manageable ones, and add comments to explain the purpose of each section of code. Additionally, they can utilize version control systems like Git to track changes and collaborate with other developers.

// Example code snippet demonstrating refactoring and adding comments

// Original code
function calculateTotal($price, $quantity) {
    $total = $price * $quantity;
    $tax = $total * 0.1;
    $discount = $total * 0.05;
    $finalTotal = $total + $tax - $discount;
    return $finalTotal;
}

// Refactored code with comments
function calculateTotal($price, $quantity) {
    // Calculate total price
    $total = $price * $quantity;
    
    // Calculate tax
    $tax = $total * 0.1;
    
    // Calculate discount
    $discount = $total * 0.05;
    
    // Calculate final total
    $finalTotal = $total + $tax - $discount;
    
    // Return final total
    return $finalTotal;
}