What has helped me is journaling ! I have an alters journal - well I have several. When they are really upset or fighting and wont let me sleep, I talk to them (even if I don't know them) and say, why don't you tell your story and let me write it out. I have seen over 7 different handwritings logged and the same alters keep writing with the same handwriting. Yes, I have seen sometimes that alters gang up on another alrer. I have read the stories. For some crazy reason, after writing it down, they settle down.
Another tip - I have 2 cd of the Ocean waves with sea guils on my walkman - when at night when everybody is uptight - I can put it on speaker and play those ocean waves and tell my alters to go play. My T says that this is good. She told me how to do it. Somedays it takes a lot of hours but after a while, they calm down and u can just see yourself sitting in the edge of the water letting the splash of the waves hit u - it does help !!
Sometimes - I let them DRAW it out - each alter will be different but they want to express themselves and it does help