I have just found an excellent video of a guy on an EN D wing showing what not to do. After an unremarkable 50% assymetric collapse, he pulls too much brake on the open side and spins the glider. As he fought the ensuing cascade, the glider did its best to fly. At one stage he had a full stall with a fairly neat tail slide but missed that opportunity to recover. With height running out, he did the right thing and threw his emergency parachute. Thankfully he landed unharmed, if in a rather precarious place on the mountain.
What the video shows is the importance of having the feel for you glider when piloting out of a collapse and also having the ability to identify when to do something and when to do nothing.
My belief is that we should do regular training to hone our canopy handling skills. You will see courses termed SIV, Pilotage, Control Courses etc. Try to get someone with an established reputation and who will analyse and build your skills.
I didn't go on a course in 2011, so am itching to get "over water" again in 2012!