How can I create a separate data partition?

The home partition holds all user data and settings. When backing up my home partition it contains a lot of data (the settings) I don't need. So I thought I could create a separate data partition and mount it to ~/Data. That would make my backups smaller and the backup process easier because all my important data is on this partition and nothing else. How can I create and mount such a partition. Is it possible to set this up during the Ubuntu 12.04 LTS installation? Another important thing would be that the places shortcuts in nautilus (documents, music etc.) should point to the directories in my data partition. Is that possible?

Thanks for your time

Once you boot from CD/DVD, or USB, and get to the installation Screen, choose Something Else.

And when you get to the screen below, and choose New Partition Table, and just follow the images below. Make sure you divide the space according to your needs /, Swap, /Data, and /Home, etc...

Note: The image below are for instructional purposes, your real life situation maybe different.