Working with Drupal commerce entities using entity_metadata_wrapper. Just a bunch of exampled copied from the web or added by me. will keep adding over time.

dc_emw.php

<?php

// order.

$order_wrapper = entity_metadata_wrapper('commerce_order', $order);

// Order id.
$order_id = order_wrapper->order_id->value();

// User detils.
$uid = $order->uid;
$email = $order->mail;

// order total object
$order_total_obj = $order_wrapper->commerce_order_total->value();
// Order total (cents).
$order_total = $order_total_obj['amount'];

// order currency code
$currency_code = $order_wrapper->commerce_order_total->currency_code->value();


// subtotal without vat
$total_ex_vat = commerce_price_component_total($order_total , 'base_price');

// total tax (in this case vat 20%)
$total_vat = commerce_price_component_total($order_total , 'tax|vat_20');

// subtotal with vat
$sub_total = $total_ex_vat['amount'] + $total_vat['amount'];

// formatted price string with currency sign
$sub_total = commerce_currency_format($sub_total, $currency_code);

// Order state 
$order_status = commerce_order_status_load($order->status);  
$order_state = $order_status['state'];
if ($order_state != 'cart') {
  	....
}

// Get the customer billing profile (this is not the wrapper object for the wrapper object don't use the ->value())
$customer_billing = $order_wrapper->commerce_customer_billing->value();
// Make sure it exists
if (isset($customer_billing)) {
  // Get the customer billing profile wrapper	
  $customer_billing_wrapper = $order_wrapper->commerce_customer_billing;
  // Get the address
  $address = $customer_billing_wrapper->commerce_customer_address->value();  
  // Get organisation name if available.
  if (isset($address['organisation_name'])) {
    $organisation_name = $address['organisation_name'];
  }
  
}	

// Line item


$line_item_wrapper = entity_metadata_wrapper('commerce_line_item', $line_item);

// get all line item wrappers from order wrapper
foreach ($order_wrapper->commerce_line_items as $line_item_wrapper) {
  // line item type
  $line_item_type = $line_item_wrapper->type->value();
  // line item type using the bundle.
  $line_item_type = $line_item_wrapper->getBundle();

  // check if a product.
  if (in_array($line_item_type, commerce_product_line_item_types())) {

    // line item title
    $line_item_title = $line_item_wrapper->commerce_product->title->value();

    // line item unit price
    $line_item_unit_price = $line_item_wrapper->commerce_unit_price->amount->value();

    // line item formatted unit price
    $line_item_unit_price = commerce_currency_format($line_item_unit_price, $currency_code);

    // line item quantity
    $line_item_quantity = (float)$line_item_wrapper->quantity->value();

    // line item total price
    $line_item_total_price = $line_item_wrapper->commerce_total->amount->value();

    // line item formatted total price
    $line_iten_total_price = commerce_currency_format($line_item_total_price, $currency_code);

    // Product
    
    // Product ID.    
    $product_id = $line_item_wrapper->commerce_product->product_id->value();
    
    // Product SKU.    
    $sku = $line_item_wrapper->commerce_product->sku->value();

    // Product image	 
    $line_item_wrapper->commerce_product->field_product_image->value();
	 
	  // Load the product.
	  $product = commerce_product_load($product_id);
    

  } else {
    // for shipping & discount line items

    // shipping/discount price
    $line_item_price = $line_item_wrapper->commerce_unit_price->amount->value();

    // shipping/discount formatted price
    $line_item_price = commerce_currency_format($line_item_price, $currency_code);

    // line item TYPE display title
    $line_ite_type_title = commerce_line_item_type_get_name($line_item_wrapper->type->value());

    // for shipping line items
    if ($line_item_wrapper->type->value() == "shipping") {

      // shipping data
      $shipping_data = $line_item_wrapper->value()->data;

      // shipping method display title
      $line_item_title = $shipping_data['shipping_service']['title'];

    }

    if ($line_item_wrapper->type->value() == 'commerce_discount') {
      // for discount line items

      // get discount display title (I suspect there might be a better way than this)
      $discount_data = $line_item_wrapper->commerce_unit_price->data->value();
      foreach ($discount_data['components'] as $key => $component) {
        if (!empty($component['price']['data']['discount_component_title'])) {
          $line_item_title = $component['price']['data']['discount_component_title'];
        }
      }
    }
  }
}

// Product.
$product_wrapper = entity_metadata_wrapper('commerce_product', $product);

// Product Price.
$price_amount = $product_wrapper>commerce_price->amount->value();
$product_wrapper>commerce_price->amount->set($new_price);   

// Stock	
$product_wrapper->commerce_stock_override->value()
$product_wrapper->commerce_stock->value()

  // Create a new product
  $wrapper = entity_metadata_wrapper('commerce_product', commerce_product_new('product'));
  $wrapper->title = $title;
  $wrapper->sku = $sku;
  // Set the price.
  $wrapper->commerce_price->amount = $price;
  $wrapper->commerce_price->currency_code = 'GBP';
  // or $wrapper->commerce_price->amount->set($price);
  // Set the new stock level.
  $wrapper->commerce_stock->set($new_stock);
	
	
// Taxonomy – term referenced
// Get the term object.
$term = $product_wrapper->field_availability->value();
// Get the taxonomy term name
$term_name = term->name;
// One liner of the above.
$term_name = $product_wrapper->field_availability->value()->name;

// Taxonomy – term referenced using a term wrapper
$term_wrapper = $product_w->field_availability;
$term_name = $term_wrapper->name->value());

// Multi value term reference fields.
$terms_wrapper = $product_w->field_availability;
foreach ($term_wrapper as $term) {
  $ex_list[$term->tid] = $term->name;
}

// Get the user from a line item
  $order = commerce_order_load($line_item->order_id);
  $order_wrapper = entity_metadata_wrapper('commerce_order', $order);
  $uid = $order_wrapper->uid->value();