Setting up password authentication for windows file sharing / samba (smb / cifs ) shares

Adding password based authentication to windows file shares / samba sharing on linux is never as simple as I'd expect. With the spread of cryptolocker (ransomware which can encrypt your network shares!)  I have been working to enhance the security and resilience of my windows samba network shares. Here are some simple pointers from my experience of setting up authentication on a Ubuntu machine running samba (tested on samba versions 3.4.7 and 3.6.3) :