Windows 8 app code optimization for localisation

For an existing Windows 8 app I require code optimization for localization purposes. What kind of work is required: The code base for the app exists and the app has been approved to the Microsoft store already. Now as next step it is required to bring the app to local markets. For this the code must be reviewed and optimized that it can be localized easily. So the requirement would not be to write a new app, your job would be to prepare the app for localization so that it can be uploaded to the windows store for any language easily.