Hi maggiemuggins,
Make sure the sidebar is displaying in iTunes. For a Windows machine, CTL+S, for a Mac, View>Show Sidebar
Also make sure that under iTunes>Preferences>Devices, the "Prevent iPods, iPhones, and iPads from syncing automatically" is checked
Then hook up your device and see if it displays under the Devices section in the sidebar. If it does, click on it to display the Device Profile screens to the right, and then click on each profile screen to make sure they are set up the way you want them for syncing information to your device, then click "Apply" or "Sync".
If the device does not show up under the Devices section in the sidebar then follow the troubleshooting steps in this article:
iOS: Device not recognized in iTunes for Mac OS X
or
iOS: Device not recognized in iTunes for Windows
Cheers,
GB