To enable push notifications, you will have to access the Accounts menu in Settings. Go to Settings > Accounts > tap on your account and then enable Sync. Make sure you are connected to the Internet and the notifications will arrive as soon as there is a new one. However, keeping SYNC activated all times will drain your battery very fast and if you're using Data connection, then this is a "lethal combination" for your phone. That's why is advised to keep the SYNC option activated only when you activate the Internet to get the news and then turn it off to conserve battery power.