Post signs that say "Shhh" !
Remind people that sound carries differently on nsg units than other places. ( don't know why, but it sure applies to our unit!)
Don't use overhead pager after 2100 and before 0800.
Use conferance room for report.
Remind people with loud voices to tone it down. I fine sometimes just looking at someone and say "Shh" does that trick.
Lower your voice when talking to someone - they will often follow suit.
If someone is very loud - point it out to them. Some people don't realize how loud they are . (of course, when I tried this with one physio because she was being very loud outside a dying pts room her response was "oh - they like to know that life is still going on!