Filer Server Structure & Best Practises

Hi,

I am looking to redo my file server. The burrent file server structure is based on departments folders and one cpublic folder.

Can any one share or guide me to some best practise or things to do to create a more effective filserver structure?

one thing to note is that being a project oriented company we do quite a lot of file sharing b/w depts. At present we just create a folders under depts. name and then share and set securty on it. Any idea how i can do it better?
the goal is to have a more controlled file server structure and security groups.

Thanks