A few questions about dampening strings have been raised in the forums lately. Hopefully this lesson will guide some of you toward solving this frustration.
Basically I have outlined two methods for keeping open strings under control.
Getting a good control over your palm muting technique is a very valuable way to not only dampen unwanted noise, but manipulate dynamics in general. This lesson does not go into much detail on the subject, but have a go at resting your hand behind the bridge when you play. Or at least keep your hand in a position that will allow you to apply light pressure on this area when you need to.
Also I pointed out a way to use the edge of your index finger to mute the next string over.
Again, I have not gone on to give you other examples. Try to stay aware of this option though. When ever a string is ringing, consider the closest finger to that string and see if you can find a way to reach, and mute, it without losing control over the current chord.