Best Design Pattern for Large Data processing methods

I have an application that I am refactoring and trying to Follow some of the "Clean Code" principles. I have an application that reads data from multiple different data sources and manipulates/formats that data and inserts it into another database. I have a data layer with the associated DTO's, repositories, interfaces , and helpers for each data source as well as a business layer with the matching entities, repositories and interfaces.

My question comes down to the Import Method. I basically have one method that systematically calls each Business logic method to read, process and save the data. There are a lot of calls that need to be made and even though the Import method itself is not manipulating the data at all, the method is still extremely large. Is there a better way to process this data?

ICustomer<Customer> sourceCustomerList = new CustomerRepository();
foreach (Customer customer in sourceCustomerList.GetAllCustomers())
{

   // Read Some Data

   // Format the Data

   // Save the Data

   // Read Some Data

   // Format the Data

   // Save the Data

   //...Rinse and repeat
}