just like you would any other dual boot setup. as you are using Linux for both OSs you only need 1 /boot partition and 1 /swap. you will need 2x /, but should be able to get away with 1 /home partition.
/dev/sda3 / <first OS>
/dev/sda4 / <2nd OS>
now as more and more systems are using LVM, sadly I dont know enough about those to help point in the right direction. but that is a standard old school partition scheme that would work for a dual boot for Linux. FYI in most distros you can choose NOT to use LVM in most cases too, but LVMs to offer a great many advantages over the standard file system. ease of expansion and reduction in size for starters as well as ease of spanning or creating RAIDs on the fly much simpler via LVM then old partition schemes.