GET ORDER DETAILS FROM ORDER ID IN MAGENTO :

To Get real order ID from order increment id in Magento: lets assume your order increment id is #10001222 and you need to get real order ID, you can use following code:

$orderIncrementId = 10001222;
$orderId = Mage::getModel('sales/order')
             ->loadByIncrementId($orderIncrementId)
             ->getEntityId();

You can get order details by order increment ID as follow:

$order = Mage::getModel('sales/order')->loadByIncrementId($orderIncrementId);

If you know the real order ID you can get order details by using following code:

$order = Mage::getModel("sales/order")->load($orderId);
To get order total value:
$orderTotalValue = number_format ($order->getGrandTotal(), 2, '.' , $thousands_sep = '');
 To get order items collection:
 
 $orderItems = $order->getItemsCollection();
 foreach ($orderItems as $item){

$product_id = $item->product_id;
$product_sku = $item->sku;
$product_price = $item->getPrice();
$product_name = $item->getName();
$_product = Mage::getModel('catalog/product')->load($product_id);
 $cats = $_product->getCategoryIds();
 $category_id = $cats[0]; // just get the first id
 $category = Mage::getModel('catalog/category')->load($category_id);
  $category_name = $category->getName();
 }
 To get shipping method from order:
 
 $shipping_method = $order->getShippingMethod();
 To get payment method code from order you can use following code:
 
 
 $payment_method_code = $order->getPayment()->getMethodInstance()->getCode();

I hope this tutorial will help you to get order details from order ID in Magento.