One of the things that I noticed while using the Mail App in Windows 8 was that I was not getting notifications for new emails which is helpful while working on desktop mode. While poking around the People Hub I stumbled across the settings to turn it on and here are the steps for you to turn on Mail Notifications.
Configuring Windows 8 Mail Notifications
From the Start Screen Launch the Windows 8 Mail App
While in the Windows 8 Mail App hover the mouse in the bottom right hand corner to bring out the charms bar then click the settings button. (From a tablet swipe right to left with your finger from the outside right of the screen to bring the charms menu up.)
Once in Settings, Click the Accounts button
Once in the accounts choose the email account that you want to setup notifications for.
Now you will see all the configuration options that are available for that account including Notifications which is at the bottom. Simple slide the button over to turn on Notifications and that’s it.