When trying to run the Select-AzureSubscription powershell command i recieved the following error even though the subscription name was correct:
No default subscription has been designated. Use Select-AzureSubscription -Default to set the default subscription.
It turns out that you need to download and update the Azure Publish Settings File before you can do this. The easiest way to do this is to run the following command and follow the prompts:
Get-AzurePublishSettingsFile