Well, the "Cheap & Easy" way would be to apply a 24 bit mask to your address (255.255.255.0)
That would give you 254 subnets (obviously more than you've asked for), but each subnet would give you 254 hosts.
SO, for location one, you'd use 10.73.1.0, 10.72.2.0, and 10.73.3.0 ... location two would use 10.73.{4,5,6}, location three would use 10.73.{7,8,9} and so on.
Remember, you'll need at least one block of addresses to subnet for your WAN connection, some "utility" subnets in the data center, perhaps some for wireless, perhaps some for VPNs .... it's better to plan for future growth and have some "spare" subnets & addresses at your disposal.
Good Luck
Scott