Watch the movie my cousin vinny over and over again....learn the words..(it works I'm italian/american -true italian- so I always lived in queens/brooklyn and wanted one I tryed it and it worked.. Take some advice from marisa tomei lol (inside joke) anyway you can also learn like saying words like this: Three- tree...what up?- wuh-dup?...-brooklyn- bruewklyn.....true italian- trew italiean..calamari- (again jus using common words)..galama...I CAN USE A BROOKLYN ACCENT AND MY REGULAR ACCENT WITH THIS TRICK....try it...
Since I figure video would help more than explaining the accent here is a video clip of Brooklyn -accent. Video.aol.com/video-detail/Rachel-and-Danielle-go-Brooklyn/980442096
I suggest you watch something like cagney and lacey, where the characters have strong ny accents. Hopefully you'll be able to pick up the dialect this way